neuropsychological assessment
TRANSCRIPT
NEUROPSYCHOLOGICAL ASSESSMENT OF ADOLESCENT POLYDRUG
USERS AND NEUROLOGICALLY IMPAIRED ADOLESCENTS
by
MICHAEL J. RATHEAL, B.A., M.Ed.
A DISSERTATION
IN
EDUCATION
Submitted to the Graduate Faculty of Texas Tech University in
Part ial Ful f i l lment of the Requirements for
the Degree of
DOCTOR OF EDUCATION
Approved
Accepted
December, 1988
10^
to\' ACKNOWLEDGMENTS
I wish to thank Dr. Paul Dixon for his support in
preparation of this study. Not only in this effort, but in
my academic career he put in to practice the theories of
learning and motivation which provided a structure for the
enthusiasm I felt for this experience. I appreciate the
support and expertise of my committee: Dr. Gerard Bensberg,
Dr. John Nevius, Dr. Arlin Peterson, and Dr. Gerald Parr.
I also thank my fellow students for their support and
stimulation throughout this process.
I would like to acknowledge the support provided by
Dr. Ray Brown who was employer, colleague, and friend
throughout this project. He contributed emotional support,
encouragement, and direction in reaching this goal.
My most intense gratitude goes to my family. First of
all, to my remarkable husband, Otto Ratheal, who not only
tolerated the stress of this experience and took good care
of me and our family, but spent countless hours preparing
the final copy. My sons, Devin and Ian, provided ongoing
inspiration to complete this task so that I could build
with Legos and make cookies without guilt. I thank my
sister, Stephani Windham, for her undying sympathetic
encouragement and finally my mother, Nita Hisey, who made
me believe I could do it in the first place.
i i
CONTENTS
ACKNOWLEDGMENTS ii
TABLES vi
CHAPTER
I. INTRODUCTION 1
Statement of the Problem 1
Purpose of the Study 3
Limitations and Considerations
of the study 4
II. REVIEW OF RELATED LITERATURE 8
History of Drug Abuse
in the United States 8
Adolescent Drug Use 13
Assessment of Cognitive Functioning . . . . 17
Cognitive Functioning of Polydrug Users . . 23
Summary and Review of Hypotheses 35
III. METHODOLOGY 38
Subjects 38
Instruments 39
Demographic and Background Data . . . 39
Medical History 39
Demographic Data 40
Psychological Functioning 40
Measures of Cognitive Ability . . . . 42
General Intellectual Ability . . 44 111
Academic Achievement 44
Memory and New Learning 45
Visual-Spatial and Visual-Perceptual Ability 46
Higher Conceptual Processing . . 46
Attention and Concentration . . 47
Design and Analysis 48
Procedures 49
IV. RESULTS 52
Descriptive Data 52
Subjects 52
Demographics on Polydrug Subjects . . 53
Medical History of
the Polydrug Subjects 55
Categories of Drugs Used 55
Psychological Functioning of Polydrug Subjects 60
Medical History of the Neurologically
Impaired Subjects 61
Clinical Impairment Ratings 61
Hypothesis Testing 63
Hypothesis 1 63
Discussion of Cinical Significance
of Group Means 63
Hypothesis 2 74
V. DISCUSSION AND CONCLUSIONS 77
Summary 77 TV
Discussion of the Study 80
Summary of Results 87
Implications for Further Research . . 89
Implications for the Professional . . 90
Conclusions 92
REFERENCES 94
APPENDICES
A. MEDICAL HISTORY QUESTIONNAIRE 100
B. DEMOGRAPHIC QUESTIONNAIRE 102
C. GLOSSARY 105
TABLES
1. DEMOGRAPHIC CHARACTERISTICS OF ALL SUBJECTS
2. DEMOGRAPHIC VARIABLES OF THE POLYDRUG GROUP
3. MEDICAL HISTORY QUESTIONNAIRE
7.
8.
9.
4. CATEGORIES OF DRUGS USED
5. FREQUENCIES OF CLINICAL IMPAIRMENT RATINGS
6. FREQUENCIES OF UNIMPAIRED AND IMPAIRED CLINICAL RATINGS
COMPARISON OF NEUROPSYCHOLOGICAL TEST RESULTS OF POLYDRUG USERS AND NEUROLOGIC GROUPS
COMPARISON OF STATISTICAL FINDINGS AND CLINICAL IMPAIRMENT RATINGS ON INDIVIDUAL TESTS .
T-TEST COMPARISON OF CLINICAL IMPAIRMENT RATINGS
54
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62
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64
70
76
VI
CHAPTER I
INTRODUCTION
Statement of the Problem
Drug use is a problem which has become part of our
"cultural clothing" (Parsons & Farr, 1981). Millions of
people are involved in the use of illegal substances and
their use has become so widely accepted that drugs such as
marijuana and cocaine have been casually accepted as part
of social gatherings. The exploration of illegal drug use
and abuse is extremely complex and assessment in this area
only began in the early 1970*s. Parsons and Farr (1981)
relate the difficulty in studying this question to the
numerous factors which contribute to drug abuse and the
historical paucity of adequate measurement tools in this
area.
The acute effects of drug use and drug abuse are well
documented in medical literature. Whether or not long-term
cognitive dysfunction is associated with intense or chronic
drug use has only recently been investigated (Grant &
Mohns, 1975; Parsons & Farr, 1981). There is a well
established pattern of cognitive deficits associated with
chronic alcohol abuse but questions remain regarding the
contribution of nutritional deficits, possible premorbid
brain dysfunction, and toxic additives to the findings.
Well controlled studies of populations using a single
category of drugs; sedatives, marijuana, stimulants,
hallucinogens, and narcotics, found no lasting cerebral
dysfunction.
It appears, however, that abuse of a single category
of drug does not represent the current drug use pattern.
Rather, a pattern of simultaneous and sequential drug use
is typical of the adults and youth currently involved in
drug use; therefore, the question of the effect of polydrug
use on cognitive functioning needed investigation. Six
studies were located which attempted to respond to this
question (Adams et al., 1975; Bruhn & Maage, 1975; Grant,
Adams, Carl in, Rennick, Judd, & Schooff, 1978; Grant et
al., 1978b; Grant & Judd, 1976; Grant et al., 1976). With
the exception of one study located in Denmark (Bruhn &
Maage, 1975), the studies were immediate precursors to, or
part of, a grant funded by the National Institute on Drug
Abuse. These investigations documented long-lasting
cerebral deficits in polydrug abusers whose mean ages
ranged from 25 to 26 years. With the increasing drug use
by adolescents and the documented trend toward polydrug use
in this population (Pandina & White, 1981), the question of
the effects of chronic, multiple drug use on brain function
needs assessment for this group.
Purpose of the Study
The research which supports a connection between
polydrug use and cognitive deficits has been done on a
young, but not an adolescent, population. Further, the
studies were completed at a time when "designer drugs" were
not being used. This study provides empirical data
regarding cognitive functioning of polydrug abusing
adolescents relative to a sample of neurologically impaired
teenagers who were matched for age. There are several
reasons why this data may be valuable to professionals
working with treatment of adolescent drug abuse:
1. Adolescent drug use is viewed as a failure to meet
the challenges of adolescent development; identification of
cognitive impairment associated with drug abuse may con
tribute to prevention arguments, to motivation for seeking
treatment, and to reduction of recidivism.
2. Identification of cognitive impairment in polydrug
abusing adolescents may assist treatment providers in mod
ifying therapeutic approaches to accommodate an individual
patient's abilities.
3. Identification of cognitive impairment in a young
population of drug abuse may suggest the existence of pre
morbid levels of cognitive deficit which could assist in
identification of a vulnerable target population for
special attention in prevention services.
This study provides additional data regarding
demographic and psychological functioning of adolescents
who are involved in polydrug abuse to a degree which has
identified them as in need of inpatient treatment.
Limitations and Considerations of the Study
This study was conducted in an inpatient hospital
treatment setting and certain limitations and restrictions
were necessary as a result of the need to avoid disruption
of the program. The patient's inpatient status was not
within the control of the examiner.
The most revealing information about the effects of
drug abuse on cognitive functioning would accurately
account for levels of drug use, both cumulative use and
intensity of single episodes of use. Obtaining a truly
accurate picture of drug use patterns from a self-report
measure has limitations. The subjects may have memory
difficulty for periods of intense drug use. A need to give
socially desirable responses may affect the patient's
reporting of drug involvement.
The procedures used in this study, neuropsychological
measures of brain functioning, are typically used to assess
identified brain pathology such as tumors, stroke, and head
injury. Their use in identifying less specific and
possibly reversible deficits is less well established and
therefore validity of the measures may be questioned.
The issue of deficits itself is somewhat ambiguous. A
child may show a pattern of strengths and weaknesses on a
psychometric measure of intelligence, and although some
abilities may fall in the borderline range of ability they
do not necessarily indicate deficient brain functioning.
The measures used must cover both broadly and in depth each
major category of ability in order to describe levels of
functioning and, even then, it is the pattern of perform
ance, rather than any individual test which truly indicates
level of ability.
The confounding effect of psychopathology on brain
function must be dealt with in attempting to describe
causal factors for any observed brain dysfunction. The
relationship of illegal drug use to psychological malad
justment has been the predominant focus of the literature
dealing with attribution of causes. Several studies
(Grant et al., 1978; Kilpatrick et al., 1976; Penk et al.,
1979) have found evidence of psychological maladjustment in
drug abusers. There is research support for dysfunctional
cognitive ability in chronic and acute schizophrenics
(Rodnight, 1983). Lezak (1983) states that "the incon
sistent or erratic expression of cognitive defects suggests
a psychiatric disturbance" (p.233). Therefore it is
important to differentiate between deficient functioning
which is related to personality characteristics and de
ficient functioning which is related to impaired brain
integrity from drug abuse.
The existence of possibly lower levels of premorbid
functioning must be differentiated from drug related im
pairment. Parsons and Farr (1981) state that performance
on neuropsychological measures is highly correlated to the
subject's general level of cognitive ability. They further
discuss the possibility that some users of illegal drugs
may have lower levels of ability to begin with, resulting
in failure experiences, which could represent a contrib
uting factor to involvement with drugs rather than a result
of drug abuse. This presents a problem because of the lack
of information about premorbid functioning on the patients
in the study. If this information were available, analysis
of individual patterns of functioning would yield compara
tive data which would be more descriptive of possible drug
effects.
Both of the subject groups in this study include males
and females. Laterality and functional differences have
been consistently demonstrated between the sexes with
females performing better on verbal measures and males on
visuospatial measures. Lezak (1983) discusses the differ
ences between males and females in deficits related to a
unilateral lesion, while men show significant impairment on
the side where the lesion is located, women show more dif
fuse deficits. The same kind of differences are found in
studies exploring the lateralization effects of handedness.
The most stringently controlled study of brain impairment
would attempt to minimize the variability of cerebral
organization within each subject group by selecting perhaps
only right-handed males but this extent of exclusion was
not possible in the present study due to the small subject
population available.
CHAPTER II
REVIEW OF RELATED LITERATURE
With the onset of public awareness regarding substance
abuse a search for causes and effects began. The problem
of the abuse of psychopharmacological drugs has been laid
at the door of parents, peers, environmental stressors, and
improper medical supervision of addictive substances. No
pattern has been empirically defined for movement from the
use of "soft" drugs such as marijuana and alcohol to "hard"
drugs including barbiturates, amphetamines, and opiates.
Nevertheless, there is evidence that drug abuse is increas
ingly best described in multiple use terms (Kornblith,
1981) and that cognitive deficits are associated with
polydrug abuse.
History of Drug Abuse in the United States
The entry of middle class, white youth into the drug
scene of the 1960's and 1970's presented a troubling phe
nomenon to our society (Josephson & Carroll, 1974). As
long as drug use was confined to a lower class, minority
population it seemed somehow less odious and more under
standable. Kissin (1982) states,
The history of drug dependence is the history of man's search for 'the occasional release
8
from the intolerable clutch of reality' through the taking into his body—by ingestion, inhalation, or injection—of some magical chemical substance, (p. 2)
It did not seem to be a societal failure when the lower
classes of an industrialized nation needed more "escape"
than other groups, but when the use of drugs became wide
spread among advantaged youth the message seemed to change.
Josephson and Carroll (1974) suggest that this phenomenon
was interpreted by parents and parental surrogates such as
schools as a threat to "self-control and the work ethic and
therefore the very moral fabric of society" (p.xvi).
Kissin (1982) and Blum (1969) review the history of
drug use. Numerous artifacts suggest the existence of beer
from about 6400 B.C. (Blum, 1969). The discovery of dis
tilled spirits made alcohol much more readily available.
Kissin (1982) indicates that the idea of the "drunkard"
appeared and there were epidemics of alcoholism among
England's lower classes until the government levied a tax
which put liquor beyond the economic reach of the poor.
Kissin (1982) indicates that the use of psychoactive
drugs was limited by geographic availability with the
earliest recorded use of marijuana in China in 2737 B.C.
For centuries the drug was known outside the Eastern cul
tures but was not widely adopted. The use of cannabis in
creased when the Napoleonic soldiers returned from Egypt
with hashish. Its early use in Europe was confined to the
10
artistic and literary elite. The early use of cannabis in
the United States followed much the same pattern.
Other botanical substances, cocaine and plant halluci
nogens, were likewise confined to specific geographical
areas initially. Kissin (1982) and Blum (1969) discuss the
use of psychoactive substances in many religious ceremonies
and Kissin notes that the peyote ritual of the Mescalero
Apaches is a legal practice in the United States today.
Availability, however, is not the only variable predicting
the use of a particular drug. Kissin (1982) states that
cocaine use has been dated to pre-Columbian societies but
spread very little to the conquering Spaniards. The author
suggests that the method of ingestion, chewing the leaves,
may have been culturally unacceptable. After the active
ingredient was isolated, it was used by a German military
doctor in the 1880's to relieve fatigue among army troops.
The later findings related to the addictive properties and
induced psychosis essentially eliminated its use medically.
Stating that "health hazards are not the only factors
underlying public concern about drugs" (p.xxi) Josephson
and Carroll (1974) discuss that while evidence is strong
for the health hazards presented by certain drugs they
continue to be protected by our society. Some drugs have
become such an accepted part of American culture that they
are not considered drugs at all. Nicotine and caffeine are
11
the most commonly used drugs throughout the world (Kissin,
1982). Blum (1969) also points out that health concerns
are not necessarily the major reason for a strong social
policy regarding specific drugs.
Ray (1978) describes four pharmacological revolutions
which paved the way for the current level of illegal drug
use. Historically, drugs were part of folk remedies, reli
gious ceremonies, and celebrations and were only available
if they were indigenous to a region. Advances in chemistry
brought about enormous changes in medicine in the 20th
century. The development of vaccines for the control of
communicable diseases represents the first of Ray's revolu
tions. Secondly, the discovery of antibiotic drugs,
including sulfa and penicillin, made major changes in
medical care. While these two revolutions were directed at
physical health, Ray's third revolution was the use of
tranquilizers in the treatment of mental illness. "The
tranquilizers introduced to the public the concept that
drugs which act on the mind could be used to return one's
mental health to normal" (Ray, 1978, p.4). The fourth
revolution was the advent of the oral contraceptive. His
perspective is that.
For the first time potent chemicals clearly labeled as drugs are being widely used by healthy people because of their social convenience. No longer are we eliminating infection to have a healthy body, neither are we reducing anxiety to have a better functioning mind. Now we are
12
adding a drug to alter a healthy body and mind because of the convenience it offers in interpersonal contacts, (p.4)
An additional chemical push, specific to the drug under
world, has been the development of the so called "designer
drugs" which mimic the effects of the more established
illegal substances.
Kissin (1982) discusses the effect of the 18th
Amendment on the level of drug use in the United States.
Although Prohibition was effective in reducing the con
sumption of alcohol and the incidence of alcoholism to
levels lower than before its adoption or after its repeal,
an unexpected side effect was the development of a powerful
institution, organized crime, which continues to exert a
major force behind the availability and sale of illegal
drugs.
Discovery of indigenous substances with mind-altering
properties proceeded from accidental ingestion or inhala
tion to intentional use in order to enhance or escape the
human condition. There were often religious connotations
to such drug use. The exact reasons for acceptance or
rejection of a particular psychoactive substance into a
culture are varied, affected by politics, economics, cul
tural values, and sometimes by accurate information related
to drug effects. In America, the Indians used a variety of
hallucinogenic plants and tobacco was indigenous as well.
13
With the immigration of Europeans, alcohol became the drug
of choice and few other substances were widely used. This
remained the case until after World War II when the effects
of hallucinogens became widely known and their availability
to the "disenchanted youth . . . led, in the late 1950s and
1960s, to the unfolding of a drug culture so powerful that
it influenced the drug-taking pattern of the world"
(Kissin, 1982, p. 14). Since that time there has been con
sistent movement toward increased drug use by younger age
groups involving a larger variety of illegal substances.
Adolescent Drug Use
Standard American values proscribe the nonmedical use
of drugs by youth with the exception of alcohol which the
culture perceives as a hallmark of adulthood (Jessor &
Jessor, 1975). Baumrind (1985) discusses the risk-taking
behavior which is typical of adolescent development and
that for the majority of adolescents who experiments with
drugs this behavior is self-limited to the stage of early
adolescence in which the teenager is seeking accommodation
of
Attainment of formal operational capacities; transition of conventional to principled morality; increased importance of peer relative to family as a socialization context; increased self-centeredness joined with enhanced role-taking ability; and, finally, jeopardized self-esteem, (p. 14)
14
The increased social acceptance of the recreational use of
marijuana and cocaine by adults in recent years has less
ened the censure for involvement with these drugs. The
most common pattern of substance abuse among teenagers is
the combined use of alcohol and marijuana (Pandina & White,
1981). Patterns of drug use by nonpatient or nontreatment
populations are difficult to obtain. The typical approach
to gathering this data is a self-report questionnaire cir
culated in public school settings. Data are also obtained
by assessing pretreatment levels of drug involvement in
patients involved in drug treatment programs. In a search
for causes of polydrug involvement by high school students,
Kamali and Steer (1976) report.
The attitudes which were related to polydrug involvement reflected a hedonistic quest for pleasant sensations and expanded creativity while simultaneously denying that drug use was potentially harmful, (p.342)
Dembo et al. (1985) discuss the sociocultural and person
ality variables contributing to drug use. In a concept
they call "relative deviance" the authors describe the view
that for inner city urban youth, drug involvement is a
prosocial behavior and is egosyntonic while for adolescents
whose cultural values proscribe drug use, it is egodystonic
and therefore more likely to be related to psychopathology.
Hawkins, Lischner, & Catalano (1985) state that factors
such as early conduct problems predict a variety of
15
antisocial behaviors including drug abuse. These authors
review research regarding aggressiveness ratings by first-
grade teachers and low academic achievement at the end of
elementary school and find support for these issues as
predictors of delinquency and drug abuse.
The investigation becomes more complicated when
current substance use patterns are considered. Although
most studies of polydrug involvement have studied drug
preferences, there are a few which have investigated
patterns of multiple use (Kliner & Pickens, 1982).
Multiple-drug use has become the norm rather than the
exception with the combination of alcohol and marijuana
being the most common (Pandina & White, 1981; Pandina et
al. 1981). In a sample of 1,970 high school and junior
high students Pandina and White (1981) found only 6% who
reported never having used alcohol or drugs. Eighty-nine
percent of this population had tried alcohol and 74% were
current users. Fifty percent had tried cannabis and 37%
were current users. This study also included a client
population which was drawn from referrals to an agency
responsible for coordinating services for troubled adoles
cents. Of the 224 subjects in the client group, 81% were
current users of alcohol and 66% were current users of
marijuana. Pandina et al. (1981) indicated that 41% of the
students in their survey used alcohol only, 17% used
16
alcohol and marijuana, 5% used alcohol, marijuana, and one
other drug, and 11% used alcohol, marijuana, and at least
two other drugs.
In a study of prisoners in a correctional facility for
men under 21 years of age, Marini et al. (1978) found 32.8%
of this population to be regularly using two drugs in
addition to alcohol and marijuana, 36.2% of the prisoners
were regularly using more than two drugs in addition to
alcohol and marijuana. In a study of polydrug use by high
school students Kamali and Steer (1976) found a multiple-
use pattern among 273 of 840 students. The most common use
pattern by this group was alcohol and cannabis.
The impact of drug use on children's lives can be in
vestigated from many perspectives. In terms of prevention,
research seeks to understand the contributing factors; peer
pressure, family dynamics, preexisting genetic vulnerabil
ity, and the effects of education programs aimed at
sensitizing children to the dangers related to drug use.
Investigations deal with the involvement of drug users in
other illegal activities and subsequently with the legal
system. Studies have also sought to correlate academic
achievement and personality factors with drug abuse.
Little attention has been directed at the cognitive
functioning of a drug abusing population of adolescents.
No studies were located which used general intelligence or
17
any cognitive measure, other than school achievement, in
assessing the characteristics of this population.
Assessment of Cognitive Functioning
Intelligence tests and other measures of cognitive
ability are based on an individual's responses to standard
ized procedures. The results are intended to describe the
person's current functioning and to reflect potential which
may not be evident from the standardized score.
When psychologists speak of potential intelligence of a child, their interpretations are based under two categories: (1) test scatter and (2) measures of intellectual deterioration. Test scatter involves both intertest patterns and intratest variability of performances. (Magnussen, 1979, p.560-561)
A common example of the first category is a child who shows
failures on early items of a task while successfully com
pleting later, presumably more difficult items. In this
case, interpretation of the child's performance usually in
volves some response characteristic such as anxiety rather
than ability.
A difference between ability and potential is also
postulated in situations where the current level of func
tioning is presumed to be lower than the level of premorbid
ability. This is the second category suggested by Magnus-
sen (1979). A clear case of this exists when there has
been a known injury to the brain. An example would be a
18
person with an injury to the left hemisphere of the brain.
In such a case, performance on measures of verbal ability
are typically uniformly low. The best measure of premorbid
language ability may be a test of oral reading. The
person's performance on such a task, which involves an
overlearned skill, is often the most accurate measure of
premorbid ability. An exception to this would be a focal
injury resulting in expressive aphasia.
A third category considered in the assessment of un-
demonstrated potential involves areas in which a child may
have lacked opportunity to develop. An example of this is
described by Kaufmann (1979) in his caution against using
instruments normed on native English speakers in assessing
the verbal ability of children who learned English as a
second language. A second example of an area of cognitive
deficit based on lack of opportunity is found in children
from backgrounds where little emphasis is placed on aca
demic achievement. That will frequently result in the
child having a limited fund of general information even
when measures of memory are unimpaired.
After Cattell (Anastasi, 1982) introduced the idea of
describing individual differences in mental ability through
testing, assessment of intelligence began to increase in
importance as an educational and psychological tool.
Spearman reflected the generally held belief that
19
intelligence was a unitary concept and "that for the
purposes of assessing the amount of general intelligence
possessed by a person any test is as good as any other, as
long as its correlation with a is equally high" (Jackson &
Messsick, 1978, p.414). A contrasting, multidimensional
view of intelligence was proposed by L. L. Thurstone
(Guttman, 1978). This perspective on intelligence
resulted from increased sophistication in statistical
methods which allowed for analysis of commonalities and
differences among mental processes. Lezak (1983) states
that
As refinements in testing and data-handling techniques have afforded greater precision and control over observations of intellectual behavior, it has become evident that much of the behavior that tests measure is directly referrable to specific intellectual functions, (p. 21)
She describes four primary categories of cognitive ability;
receptive, memory and learning, thinking, and expressive.
In order to describe the specificity of neurological im
pairment, Lezak provides the following example.
A brilliant research scientist was struck on the right side of his head by falling rock while mountain climbing. He was unconscious for several hours and then confused for several days, but was able to return to a full research and writing schedule shortly thereafter. On psychological tests taken six weeks after the injury, he achieved scores within the top 1-5% range on al1 tests of both verbal and visuoconstructive skills, with the single exception of a picture-arranging test requiring serial organization of cartoons into stories. On
20
this test his score, at approximately the bottom tenth percentile, was almost in the border 1ine defective ability range. He was then given a serial reasoning test involving letter and number patterns which he answered correctly, but only after taking about 25 minutes to do what most bright adults can finish in 5. He reported that his previous high level of work performance was unchanged except for difficulty with sequential organization when writing research papers, (p. 21-22)
The testing and interpretation of findings in this situa
tion is a neuropsychological assessment. It involves an
evaluation of cognitive ability in a variety of areas to
provide a picture of current functioning. This includes
comparative strengths and weaknesses and prediction of un-
demonstrated potential and premorbid ability.
The history of neuropsychology is reported by Horton
and Puente (1986). The authors report that attempts to
localize brain deficits are recorded as early as 2500 and
3000 B.C. Paul Broca was responsible for pinpointing the
first neurological cite of a specific function with his
studies in aphasia and this work was furthered by Kurt
Goldstein's study of soldiers with traumatic head injuries.
Parallel to the work of European scientists were the
individual case studies by Russian A. R. Luria. Neuropsy
chological assessment began as a companion to neurological
and psychiatric evaluations of patients' abilities. Much
of the early research dealt with establishing the credibil
ity of the assessment procedures so that the tests could
21
accurately predict the cite of a lesion or trauma. With
the advent of medical technology which can provide pictures
of the brain, computed tomography (C.T.) scans, electro-
encephlagrams (EEG), and magnetic resonance imaging (MRI),
this function of neuropsychological assessment became less
important.
Despite the fact that the medical procedures could
tell the physician what the brain looked like more effect
ively than neuropsychological tests, they could not provide
information about the functional ability of the brain. The
task of defining strengths and weaknesses and identifying
subtle forms of brain deficit remained the function of the
neuropsychologist. In addition to providing descriptive
information it is the clinician's responsibility to
(1) establish the existence of any cognitive deficits related to this insult, (2) establish the relative magnitude of this insult, (3) estimate the patient's ability to return to his previous life-style, and (4) suggest remediation programs. (Crockett, Clark, & Klonoff, 1981, p. 2)
Although neuropsychology began as an adjunct to med
ical treatment, the research boundaries have widened so
that the techniques are currently used in assessment of
learning disabilities, personality, and behavioral disturb
ances. Application of neuropsychological assessment to
clinical, rather than medical, populations began approx
imately 20 years ago and there is extensive literature
22
on the effects of chronic alcohol abuse on cognitive
functioning (Parsons & Farr, 1981). Crockett, Clark, and
Klonoff (1981) cite studies using neuropsychological
evaluation in examination of delinquent behavior which
suggest that mild left hemisphere dysfunction, combined
with poor environmental controls, predict delinquency.
Dorman (1982) correlated personality and neurotic variables
of school-age boys, seven to 14 years old, with neuropsy
chological performance and found that in the younger age
group, seven- and eight-year-olds, disorders of conduct
were related to impaired cognitive functioning. The author
posed the question of whether cognitive deficits were
manifested in extraverted, uninhibited behavior as well as
on measures of intellectual function or if certain patterns
of psychopathology negatively affect cognitive functioning.
This kind of research represents a new application of the
procedures in a field which only began at the start of the
20th century. While the potential for furthering the
knowledge of brain-behavior relationships is immense, ap
plications of neuropsychological procedures in these areas
reach beyond the traditional use of the techniques. This
study involves such an expansion of these psychometric
techniques in evaluating the effects of polydrug use on
cognitive functioning.
23
Cognitive Functioning of Polydrug Users
The clinical impression of the "burned-out" drug user
and information regarding the powerful mind-altering
properties of drugs have raised the question of possibly
diminished cognitive capacity, either long-term or with a
very slow rate of recovery. The effects of chronic alcohol
use are well documented and are reflected in deficits in
brain functioning. The most dramatic picture of alcohol-
related dysfunction is presented in the Wernicke-Korsakoff
Syndrome. This is an amnestic syndrome resulting from
chronic alcoholism and the nutritional deficits which
accompany it. The more ubiquitous disability associated
with chronic alcohol abuse is poor adaptive functioning.
Two areas of cognitive deficit, abstract reasoning and
complex perceptual motor ability, are consistently reported
in the research on the neuropsychological functioning of
alcoholics (Kleinknecht & Goldstein, 1972).
In review of the literature examining the effects of
heavy drug use on neuropsychological test performance
Parsons and Farr (1981) and Grant and Mohns (1975) found no
evidence of cognitive deficits resulting from prolonged
heavy drug use except during intoxication. Their reviews
included studies on marijuana, sedatives, stimulants,
hallucinogens, and narcotics. These studies were inves
tigations of the abuse of a single category of drug.
24
Grant et al. (1978) state that
. . . It is no longer meaningful to describe North American drug abusers simply as "marijuana users" or "stimulant abusers" since there is every likelihood that such groups will also have substantial experience with alcohol, sedatives, tobacco, and perhaps opiates. (P.1063)
Rather, a pattern of simultaneous or sequential abuse of
drugs was found to be typical of persons heavily involved
in drug-taking. Simultaneous use indicates involvement.of
more than one drug category in order to obtain a certain
desired result. Sequential use indicates involvement of
more than one drug category in sequence in order to
counteract or enhance the effects of the first drug.
Neuropsychological assessment of this population revealed
organic impairment in subjects with heavy, multiple-drug
use histories.
Parsons and Farr (1981) discuss the difficulty of
assessing the cognitive effects of drug usage in polydrug
abusers. Evaluation of this group presents significant
confounding variables to an understanding of the observed
deficits. Poor nutritional intake, psychopathology, head
injuries related to intoxication and the relative con
tribution of various drug categories are all possible
contributors to the cognitive impairment. The fact appears
to be, however, that the real world presents a population
in which arbitrary distinctions are difficult to justify
and may not exist.
25
In one of the first studies to address the possible
chronic, deleterious effects of polydrug abuse on intel
lectual and cognitive functioning, Bruhn and Maage (1975)
studied 87 men in the state prison system of Denmark. The
subjects were separated into four categories of drug in
volvement based on responses to a clinical interview
covering drug history; 1) no drug experience; 2) marijuana
and hallucinogens; 3) marijuana, hallucinogens, and amphet
amines; and 4) marijuana, hallucinogens, amphetamines, and
narcotics. The subjects were administered the WAIS and
measures of abstract reasoning ability, learning and memory
tests, auditory perception, analysis of complex designs,
and a continuous reaction time test. The authors found no
difference between controls and drug users, or among cat
egories of drug users on any measure of cognitive ability.
In their review of these findings. Grant et al. (1976)
suggest that lack of discriminate results may have been due
to the statistical analysis of differences on each assess
ment procedure rather than analysis of response patterns
which is the clinical method of determining deficit from
premorbid functioning.
In a second pioneering study, Adams et al. (1975)
completed neuropsychological evaluation of 51 polydrug
users in a Detroit treatment center. This was an inpatient
study and the initial assessment with an expanded Hal stead-
26
Reitan battery was completed within three days of
admission. A repeatable portion of the battery was admin
istered three times; approximately one week after initial
assessment, at the end of the first month of hospitaliza
tion, and at discharge. The average age of the population
was 26.7 years with 11.8 years of education. A comparison
of the individual procedures to normative data showed the
polydrug population to be functioning in the impaired range
on all measures except one (Trail Making Test, Part A).
The subjects of the Adams et al. study were compared to
data provided by the San Diego Polydrug Study Unit on nor
mals, general medical patients, and neurological patients,
matched for age and education. The results showed no sig
nificant differences between the polydrug subjects and the
neurological patients with the exception of one procedure.
The performance of the polydrug group was poorer than the
normals on eight measures (Category, Speech, Tapping with
both hands. Trails A, Trails B at the P<.05; grip strength
with both hands at the P<.001 level; and Rhythm at the
P<.01 level). These findings describe the cognitive func
tioning of the polydrug users as similar to patients with
identified neurological impairment. The authors did find
improvements on the repeatable measures battery but were
unable to rule out the possibility that these were due to
practice effects and learning.
27
Adams et al. (1975) completed a cluster analysis on
the data from their polydrug subjects and found two
patterns of performance. For one group. Performance IQ
exceeded Verbal IQ by 12 points. This group included no
high school graduates and the subjects produced poor scores
on measures of academic achievement. This group was
younger, had more failures on tasks involving receptive
language and reported using fewer categories of drugs but
using these heavily. The authors suggest
For the group [cluster 1], there is a clear superiority in performance IQ. In investigating the subjects who could be classified into the group we found that 1) No subject in the cluster had finished high school 2) All achievement scores (WRAT) were uniformly low 3) Performance IQ was an average 12 points better than verbal IQ 4) The groups reported using fewer kinds of drug more intensively 5) The group tended to be younger than the rest of the sample and 6) More receptive language errors were present in the testing records, (p. 159)
The subjects in the second cluster had better academic re
cords. They reported using a wider variety of drugs but
less heavily "tending to use barbiturates and narcotics,
rather than marijuana, amphetamines, or the heavier hallu
cinogens" (Adams et al., 1975, p. 159). The second group
also showed more psychopathology based on the MMPI
profiles.
A preliminary study by Grant et al. (1976) investi
gated the long-term cognitive effects of heavy polydrug
use. The authors compared the performance of 22 young men
28
who were admitted to a residential treatment program for
youthful narcotics addicts. The subjects were assessed at
a mean of 60 days after admission in order to minimize
toxic and withdrawal effects on the testing. The Halstead-
Reitan neuropsychological battery was administered. The
results were compared to matched groups of medical patients
and neurological patients. Each profile of test results
was submitted to an experienced neuropsychologist for
rating in one of two categories, normal or abnormal. The
findings indicated that half of the polydrug subjects were
functioning in the impaired range of mental ability. In
dividual measures on which they performed more poorly
included Performance IQ, Full-scale IQ, Picture Completion,
and Object Assembly on the WAIS; Category Test; nondominant
time on TPT; and time for both hands on the TPT. The drug
users performed better on the Rhythm Test than the medical
controls. The investigators were unable to establish a
specific pattern of drug use relative to neuropsychological
results.
Another question explored by the authors was the
relationship of a history of head injury to cognitive
functioning. A high incidence of head injury for heavy
drug users is revealed in medical histories which include
numerous falls and motor vehicle accidents related to
intoxication (Parsons & Farr, 1981). This study did not
29
support such a relationship in their small subject
population. Further, the authors did not find that
psychiatric illness was related to cerebral dysfunction.
The investigators discuss their results very cautiously,
stating that "Those individuals who demonstrate neuropsych
ological abnormality, according to our evaluation of these
tests, would be said to have mild, generalized cerebral
dysfunction" (p. 977). They also state that the possi
bility of a lower level of premorbid functioning could not
be entirely ruled out.
Following these efforts, a collaborative study
supported by the National Institute of Drug Abuse was es
tablished. Eight polydrug treatment centers participated
in an investigation of the neuropsychological performance
of their patients. In the studies by Grant and his asso
ciates (Grant & Judd, 1976; Grant, Adams, Carlin, Rennick,
Judd & Schooff, 1978; Grant et al., 1978b) 37% of their
population scored in the impaired range on neuropsych
ological measures. The subjects were 151 persons seeking
treatment at one of the designated centers. The comparison
group was 59 volunteers who were screened for demographic
similarities to the drug abuse group. The assessment
included administration of the Halstead-Reitan battery
initially and at a three-month follow-up.
30
In these studies, evaluation of cognitive deficits was
based on the clinical judgment of a neuropsychologist's
rating of the individual profiles in one of six categories
Better than average performance; average performance; borderline, atypical, but not clearly deficient performance; mildly impaired performance; moderately impaired performance; and severely impaired performance. (Grant et al., 1978b)
The relationship of drug use to neuropsychological perform
ance was evaluated by multivariate analysis of variance
(MANOVA), with group membership and clinical rating of im
pairment as independent variables. The results indicated
that heavy use of CNS depressants and opiates was related
to increased neuropsychologial impairment. Factor analysis
of the assessment instruments resulted in four factors 1)
general verbal intelligence, 2) a nonverbal factor involv
ing visual motor, tactual, and perceptual skills, 3) simple
language perception and psychomotor speed, and 4) motor
strength. The polydrug group scored poorer than normals on
factors 1, 2 and 4. Reanalysis of the data, controlling
for the contribution of education, removed verbal intelli
gence, factor 1, from the Main Effects. The authors felt
that the error variance involved in factor 4, grip
strength, and its small contribution to the overall solu
tion hindered interpretation of this factor. The final
result was the finding that both the psychiatric group and
the polydrug group performed significantly (fi<.01) poorer
31
on the nonverbal measures (WAIS-R: Digit Symbol, Picture
Completion, Block Design, Picture Arrangement, Object
Assembly and on the TPT: memory and location).
The interpretation of these data is problematic,
however, due to the difficulty in distinguishing cognitive
deficits based on drug use and deficits based on serious
psychopathology. In the Grant et al. study (1978b), 26% of
a matched psychiatric population scored in the impaired
range as well. Parsons and Farr (1981) note two factors
which complicate an understanding of the data on the
effects of polydrug use,
To separate neuropsychological impairment due to prolonged polydrug use from that associated with more serious psychopathology remains a pressing problem in this research. Second, and perhaps related to the life-style and the psychopathology issues, these investigators [Grant et al.] also noted that polydrug abusers, as a group, report greater instance of traumatic head injury (23%) and severe headache (28%) than either psychiatric control or nonpatient control group, (p.348)
Grant and his associates answer this issue by describing
the research on the Halstead-Reitan battery with schizo
phrenics (Lacks et al. 1970; Klonoff et al. 1970). They
indicate that persons diagnosed as schizophrenic account
for most of the variability in the psychiatric control
group and that only three of their polydrug subjects were
diagnosed as schizophrenic.
32
In concluding their findings Grant et al. (1978b)
state.
It is striking that among the polydrug abusers, only depressant and opiate drugs could be related to observed impairment. . . . We interpret our data and previous reports to suggest that heavy, persistent amphetamine use is not related to neuropsychological impairment in most youthful users, although a few persons might indeed be at risk for idiosyncratic reasons (e.g., preexisting hypertension, vasculitis, or allergic diathesis) yet to be determined, (p. 1071)
They also indicate, based on the three-month follow-up
testing, that the deficits apparent at initial testing
showed little reversibility. They discuss the implications
for the treatment of patients experiencing cognitive
deficits and suggest that these patients should be directed
toward
Highly structured, practically oriented interventions in which communications are simple and straight forward than to therapies producing high emotional arousal (and further neuropsychological disorganization), such as encounter groups." (Grant, Adams, Carlin, Rennick, Judd, & Schooff, 1978, p. 183)
In response to contradictory findings regarding the
cognitive effects of inhalant abuse, Korman et al. (1981)
studied 68 inhalant-abusing and 41 other-drug-abusing
adolescents. All of the subjects were classified as poly
drug users and were given a neuropsychological battery.
Analysis of covariance revealed a main effects difference
between the two groups. The inhalant abusers performed
significantly more poorly (p<.05) on 20 of the individual
33
assessment procedures. The finding of impairment on both
global and specific measures of ability led the authors to
conclude that the deficits represented diffuse brain
impairment. Although the authors did not apply clinical
impairment ratings to the polydrug subjects, scores on the
20 measures showing significant differences were provided.
Application of clinical ratings to these scores describes
the inhalant abusers as functioning in the moderate range
of impairment while the polydrug subjects' functioning
appeared to be in the mild range of impairment suggesting
that the entire population of this study showed diffuse
brain dysfunction with greater impairment by the adoles
cents emphasizing inhalant abuse.
Although neuropsychological assessment of cognitive
functioning appears to be a fruitful approach to describing
certain clinical groups there are methodological problems
which must be acknowledged. When comparing cognitive var
iables, issues such as age, education, and socioeconomic
status (SES) are known to have effects on scores. Parsons
and Farr (1981) describe the "thorny, but unavoidable
issue" (p. 347) of general intelligence. There are two
aspects to the issue of general cognitive ability. First,
if groups are to be judged as equal for comparative
purposes the equality of ability should be a premorbid
measure. Second, the authors state that if the subjects
34
are pulled from a population with higher levels of general
ability, such as college students, their abilities may be
resistant to demonstrating deficits as measured by neuro
psychological instruments. General intellectual ability is
highly positively correlated with the outcome of cognitive
functioning subsequent to brain injury. Symonds (as cited
in Lezak, 1983) states "It is not only the kind of injury
that matters, but the kind of head."
Reliable measures of premorbid ability are difficult
to obtain because few subjects would have received assess
ments previous to the development of the clinical concern.
Lezak (1983) reports two methods of estimating premorbid
ability. It should be noted that she is discussing these
variables as they relate to assessment of individual
patients, not groups. One method involves choosing a
cognitive measure which has been shown to be resistant to
the effects of brain damage and using this as a benchmark
against which to evaluate all other performance. The
Vocabulary and Picture Completion subtests of the Weschler
scales and reading test scores from academic achievement
measures are often used because of the supposed resistance
of old, overlearned skills to the effects of cognitive
dysfunction. These measures are not usually thought to be
accurate predictors of premorbid ability in patients with
left hemisphere damage.
35
Summary and Review of Hypotheses
The review of the literature establishes the
impairment of cognitive functioning as the result of poly
drug use involving certain categories of drug use. In the
best controlled, most extensive of these studies. Grant et
al., 1978b, the findings suggest that areas of dysfunction
involve nonverbal ability in visual-spatial, tactual-
spatial and visual-perceptual areas. These are the areas
commonly thought to be most sensitive to brain impairment.
These deficits were found in polydrug abusers involved with
depressants and opiates. Other drug categories were not
related to observed impairment. The subject populations in
the preceding research were young adults. Demographic
research regarding drug use indicates a continued downward
trend in age in the use of drugs and establishes the norm
of polydrug usage in those adolescents using drugs.
As the result of this review of the literature the
pertinent question regarding the cognitive functioning of
adolescent polydrug users is whether they exhibit cognitive
deficits relative to performance on neuropsychological
assessment procedures. In order to respond to this
question the following hypotheses will be investigated:
Hypothesis 1. Adolescents in a drug addiction
treatment program will demonstrate cognitive functioning
on neuropsychological measures of brain function which
36
will not significantly differ from adolescents who are
neurologically impaired.
The suggestion that the cognitive ability of polydrug
abusing adolescents will resemble that of neurologically
impaired teenagers is supported by the findings of Adams et
al. (1975) and the results of the national collaborative
study directed by Igor Grant (Grant, Adams, Carlin,
Rennick, Judd, & Schooff, 1978; Grant et al., 1978; Grant
& Judd, 1976, Grant et al., 1976) in which polydrug users
in their early 20's were found to experience "mild
generalized cerebral dysfunction" (Grant et al., 1976, p.
977).
Hypothesis 2. Adolescents in a drug addiction
treatment program will demonstrate cognitive deficits on
neuropsychological measures of brain function based on a
clinical pattern analysis of an experienced neuropsych
ologist.
Grant et al. (1978b) used clinical assessments of
experienced neuropsychologists as the best measure of
levels of deficit. They recommend this procedure because
the mean scores of groups are not reflective of the func
tioning of the individual and because analysis of the
pattern of performance, relative strengths and weaknesses,
is the clinical basis of assessing neuropsychological
deficit. This hypothesis suggests that if the pattern of
37
cognitive performance by the polydrug abusing adolescents
looks like that of someone who has impaired functioning
then their ability can be described as impaired.
CHAPTER III
METHODOLOGY
The review of the literature related to adolescent
drug use and the possibility of related cognitive deficits
suggests several areas for investigation. As the result of
previous research findings the current investigation was
proposed to test the hypotheses presented in the previous
chapter. This chapter describes the research design,
methodology, and analysis of the data.
Subjects
The polydrug subjects of the study were inpatients at
a private psychiatric hospital in a southwest community.
Participation was voluntary and involved signed permission
by the patient, the parents, and the attending physician.
Initial screening was done to determine if there was
evidence of acute neurological impairment such as previous
head trauma, acute or chronic physical disease, gross
psychopathology such as psychosis or schizophrenia, and
sensory or motor deficits which would impede the subject's
performance of the test battery. No subjects were excluded
from the study for these reasons. Detoxification of the
subjects was assessed through evaluation of medical staff
based on urine drug screening and the subjects' behavior.
38
39
The patients at the hospital represent the middle and
upper-middle socioeconomic strata.
The determination of substance addiction for the
inpatient population was based on the admitting diagnosis
of the attending physician in compliance with the defini
tion of "substance addiction" of the hospital. These
criteria were consistent with the Diagnostic and Statis
tical Manual of the American Psychiatric Association
(1980).
The second group of subjects were adolescents who had
been evaluated subsequent to significant neurological
trauma. Their neuropsychological testing was conducted as
part of the routine medical follow-up in order to assess
cognitive functioning and to develop recommendations for
treatment.
Instruments
Demographic and Background Data
Medical History
The Medical History Questionnaire (Grant, Adams,
Carlin, Rennick, Judd & Schooff, 1978) evaluates the pres
ence of trauma or illness which could account for abnormal
neurological findings. This questionnaire was used with
the polydrug subjects to assess medical events which might
40
establish prior cause for the existence of neurological
dysfunction. (See Appendix A.)
Demographic Data
Following the recommendations of Gersick et al. (1980)
the demographic data covered age, sex, socioeconomic
status, religion (denominational affiliation and degree of
religiosity), level of academic achievement, race and
ethnicity. Through the interview with this instrument the
polydrug subjects also reported information on peer,
family, and community variables. The demographic question
naire appears in Appendix B.
Psychological Functioning
The Minnesota Multiphasic Personality Inventory (MMPI)
(Hathaway & McKinley, 1967) is the most commonly admin
istered objective personality instrument. This inventory
is completed by all adolescent inpatients at the psych
iatric hospital. The inventory consists of 566 true-false
questions. The responses are then scored on 10 clinical
scales describing major classifications of psychopathology.
Four validity scales are included which evaluate the
subject's attitude toward the test. This instrument is
criterion referenced so that responses are compared to
responses of criterion groups such as hypochondriacal and
psychopathic deviance. As Anastasi (1982) points out, one
41
weakness of the MMPI is that each scale was developed by
comparing the criterion group to the normative sample
rather than criterion groups to one another. High cor
relations among the diagnostic scales call into question
their ability to differentiate among diagnostic categories
(Anastasi, 1982). Retest reliability is reported to range
between .50 to the low .90's (Hathaway & McKinley, 1967).
A particular difficulty arises with application of the MMPI
to the special population of this study. Adolescent norms
are available (Green, 1980) but adequate interpretation of
the findings is still uncertain. Green (1980) suggests
the use of adult interpretive data based on adolescent
norms. This is the format which was used in this inves
tigation.
The Beck Depression Inventory (BDI) (Beck & Steer,
1987) is a widely used instrument in quantifying depressive
symptoms in adults and adolescents. It is a self-report
questionnaire of 21 items to which the person responds on a
four-point Likert scale. Interpretation of the scores is
based on total points and evaluation of critical items
relating to suicidal ideation and hopelessness. The manual
suggests the following guidelines for evaluating individual
scores:
Scores from 0 to 9 are considered within the normal range or asymptomatic; scores of 10 to 18 indicate mild-moderate depression; scores of 19 to 29 indicate moderate-severe depression;
42
and scores of 30 to 63 indicate extremely severe depression, (p. 7)
Test-retest administrations of the BDI in clinical
populations should reflect improvement after exposure to
therapeutic treatment and therefore reliability coeffi
cients vary depending on the population. Test-retest
correlations for psychiatric patients ranged from .48 to
.86 while studies of nonpsychiatric patients ranged from
.60 to .90. With regard to content validity the scale
reflects the diagnostic criteria associated with depres
sion in the DSM-III with the exception of symptoms which
were felt to produce a high number of false positives. The
authors indicate that discriminant validity has been shown
by the BDI ability to discriminate among diagnostic catego
ries. Construct validity has been evaluated against the
concept of hopelessness through the Beck Hopelessness
Scale and has been found positively related to the BDI.
The BDI has been assessed for concurrent validity with the
MMPI-D Scale, Zung Self-rating Depression Scale, psych
iatric ratings and correlations range from .55 to .73 (Beck
& Steer, 1987).
Measures of Cognitive Ability
Successful performance of a cognitive task is the re
sult of the ability to execute the components which make up
that task. Poor performance may be the result of the loss
43
of one contributing skill and not others. Not all
investigators agree about the primary and secondary abil
ities on cognitive tasks. This is clearly seen in the
three most popular classification systems for the WISC-R.
Kaufmann (1979) discusses his factor analytic studies,
Bannatyne's recategorization system, and Guilford's
structure-of-intellect model and describes the varying view
which each approach takes regarding the underlying abil
ities of the subtests of this instrument.
There are also broad theoretical differences regarding
the way in which the brain functions. The most widely
accepted approach to understanding brain-behavior rela
tionships in the Western world is the lateralization of
function theory. In this theory language-analytical skills
are thought to be the function of the left hemisphere of
the brain while spatial-intuitive skills are the function
of the right hemisphere. This view will be followed in
interpretation of the test data in this study because the
related literature used this approach and therefore it
provides the most comparative data. Further, the
descriptions of patterns of cognitive ability, relative
strengths and weaknesses, will follow this approach and are
consistent with the interpretations of Reitan and Wolfson
(1985) and Lezak (1983).
44
General Intellectual Ability
The age-appropriate form of the Wechsler scales was
used as a measure of the general intelligence of the sub
jects. The results on the WISC-R and WAIS-R provide the
basis from which all major neuropsychological test bat
teries proceed (Lezak, 1983). The Full Scale IQ and the
Verbal and Performance IQ's are used extensively in edu
cational settings to estimate academic functioning. In
neuropsychological assessment of cognitive ability the
subtests of the Wechsler scales are typically evaluated
individually according to the components of ability thought
to affect performance. Split-half reliability for the
three global intelligence measures are .97, .93, and .97
for Verbal, Performance, and Full Scale IQs, respectively,
for the WAIS-R and .94, .90, and .96 for the WISC-R
(Wechsler, 1974; Wechsler, 1981). Both versions of the
Wechsler scale have been found to have high correlations
with academic achievement and with the Stanford-Binet.
Academic Achievement
The Wide Range Achievement Test - Revised (WRAT-R)
(Jastak, Bijou, & Jastak, 1984) was administered to assess
the subject's level of academic achievement in the tradi
tional areas of spelling, reading, and math calculation.
Test-retest reliability was determined from the normative
45
group. For the ages included in the study the results were
.90 for reading, .89 for spelling, and .79 for arithmetic.
The content validity of the subtests is clear in that they
are meant to measure basic academic skills. Item diffi
culty was determined by the Rasch method of mathematical
analysis of ability and difficulty and indicated that the
item reflects a full range of difficulty. Construct valid
ity is supported by the high item separation reliability
coefficients which indicates that the measures are sensi
tive to developmental changes across the ages included.
Concurrent validity reflects that the WRAT-R is comparable
to other achievement measures with correlations in the high
.60's, .70's, and .80's (Jastak, Bijou, & Jastak, 1984).
Memory and New Learning
The Auditory-Verbal Learning Test (AVLT) (cited in
Lezak, 1983) is used to assess the subject's ability to
learn new verbal material. A series of 15 words is pre
sented orally by the examiner after which the subject is
requested to say as many as are remembered. The list is
presented four additional times to assess the efficiency
and rate of learning. Reliability information was un
available on this instrument. Concurrent validity was
supported by the finding that recall of the number of words
on the AVLT is similar to that of digits forward of the
46
Wechsler Digit Span subtest. Miceli et al. (1981) found
that a modification of the AVLT discriminated well between
patients with right and left hemisphere lesions.
Visual-Spatial and Visual-Perceptual Ability
The Complex Figure Test (CFT) (cited in Lezak, 1983)
is a complex visual-perceptual drawing task which includes
a recall trial. The subject is presented a design and
asked to reproduce it on a blank sheet of paper. Erasures
are permitted. The subject is not informed of the recall
trial of the task. After an intervening and cognitively
unrelated task, the subject is asked to draw the figure
from memory. The task assesses visual-spatial perception,
organization of complex visual information, and visual
memory. No reliability information was available on this
instrument. Discriminant validity is suggested by the
consistent ability of the figure drawing to differentiate
between localized lesions (Lezak, 1983).
Higher Conceptual Processing
The Wisconsin Card Sorting Test (WCST) (Heaton, 1981)
was selected to assess abstract reasoning ability. This is
a deductive reasoning task which requires the subject to
identify simple categories and develop and maintain correct
response sets based on feedback from the examiner. The
47
subject is given two decks of 64 cards each and asked to
match each of the cards to one of four key cards (marked
with one red triangle, two green stars, three yellow
crosses, and four blue circles). The subject's cards vary
randomly on color, number, and shape. The principle of
correctness is established by the examiner and must be
deduced by the subject by the "correct" or "incorrect"
verbal feedback provided by the examiner to each attempted
match. After the subject has made 10 consecutive correct
responses, the examiner shifts to another sorting
principle. Problems on this instrument can come from
difficulty identifying the categories, perseveration to an
incorrect category, or shifting to an incorrect category
before the criterion is met. No reliability information
was available on this instrument. Construct and discrim
inant validity are supported by high correlations with the
WAIS Full Scale IQ and the Halstead-Reitan Battery Average
Impairment Rating when normals and brain damaged patients
were compared.
Attention and Concentration
The Trail Making Test combines two parts which assess
visual scanning and complex attentional functions. On Part
A the subject is required to connect "as quickly as he
can," in consecutive order, a set of circled numbers. On
48
Part B the subject must perform the same task but alternate
between numbers and letters (e.g., 1-A-2-B). Digit Span
would be an example of the simplest task of attention and
recall, while Part B of the Trail Making Test is a complex
task of visual tracking, conceptual tracking, and ability
to shift response sets appropriately (Lezak, 1983). Lezak
(1983) found test-retest coefficients of .78 for Trails A
and .67 for Trails B. The author found significant
(e<.001) practice effect on Trails A while Trails B did not
improve significantly.
Design and Analysis
The results of the performance of the polydrug group
were compared to a matched sample of neurological patients.
The t-test was used to statistically evaluate these
comparisons.
The data were reviewed by a certified psychologist
with clinical training and three years experience in
neuropsychological assessment. The clinician rated the
subject's performance on a six-point scale ranging from
above average ability to profound cognitive impairment.
The rater was blind to the subject's group membership and
reviewed the pattern of performance to determine the im
pairment rating. In the analysis of these data the first
three categories (above average, average and mildly
49
impaired) were classified as "unimpaired" with the
remaining three categories (moderately, severely, and
profoundly impaired) classified as "impaired." This
grouping is consistent with the procedures used in the
national study by Grant, Adams, Carlin, Rennick, Judd,
Schooff, et al. (1978). The t-test was used to provide a
comparison of the performance rating of the polydrug and
the neurological groups.
The independent variables were group membership with
the dependent variables being the cognitive measures and
the overall impairment ratings.
Procedures
The investigator administered the age appropriate
Wechsler scale and the neuropsychological procedures. Each
subject was told that participation was voluntary and would
not affect the course of treatment and that consent could
be withdrawn at any time. The researcher chose to admin
ister the cognitive instruments in the same order to all
subjects. An alternative would have been to systematically
vary the presentation. Varying the instruments would have
controlled for fatigue and motivation factors. This was
not done, however, so that the results would provide the
most valid comparison to the findings of the neurologically
50
impaired subjects who had been previously tested in that
format.
The medical history questionnaire and the demographic
information were obtained during an interview with the
subject at the time of the testing. The MMPI and BOF were
administered by hospital personnel as part of its asses
sment procedures. The standard format at the hospital
involved the use of a computer administration and analysis
of the responses on the MMPI.
Due to the schedule of therapeutic activities in which
the polydrug subjects were involved, their testing was
typically completed during two sessions on consecutive
days. The total time required for administration of the
battery was approximately five hours. This did not include
completion of the MMPI which was scheduled by the hospital.
The testing of the neurologically impaired subjects was
typically done within the same day with three hours of the
testing completed in the morning, a break for lunch and the
remaining two hours completed in the afternoon.
The data on the neurological subjects represented
patients who had been tested over the previous five years.
The evaluations had been completed by the staff of a
rehabilitation facility in the same community as the
hospital. When multiple assessments on a patient were
available, the most recent one was chosen in order to
51
reflect a stable picture of the patient's ability and to
minimize the acute disorienting effects of the injury on
the test results.
The clinical rater had no prior knowledge of the
subjects. The data on each individual's performance was
presented on a summary sheet on which there was no
identifying information.
CHAPTER IV
RESULTS
This study was a comparison of two groups of adoles
cents on measures of cognitive ability. One group was
receiving inpatient treatment in a psychiatric hospital
related to substance abuse. The other group was comprised
of adolescents with medically substantiated neurological
impairment related to closed head injuries or neurosurgery.
The neurological subjects were tested over a three-year
period of time in a rehabilitation center. The performance
of all subjects was compared to available normative data.
The purpose of the study was to determine if adolescent
polydrug abusers would show cognitive deficits on neuro
psychological measures which are commonly used to determine
functional ability after neurological trauma.
Descriptive Data
Subjects
The subjects studied were 31 adolescents, 16 polydrug
abusers and 15 teenagers with a history of neurological
trauma. Their ages ranged from 12 to 19 years with a mean
age of 16.7 years. The subjects in the drug group were
somewhat younger than in the neurological group but the
differences were nonsignificant, t(29)=-0.76, fi<.45. There
52
53
were 22 Anglos and nine Hispanics. The subjects comprised
two intact groups, polydrug abusers and neurologically im
paired. Table 1 presents this information for each group.
Demographics on Polydrug Subjects
Demographic information on the polydrug subjects was
collected by the examiner in an interview at the time of
the testing. Corresponding data on the neurologic group
were unavailable because they were tested prior to the
initiation of the study. Typical subjects from the poly
drug group were Protestant and described themselves as
mildly religious. The middle class socioeconomic strata
predominated. Nine of the 16 subjects reported a per
ception of having sustained cognitive impairment as the
result of drug use. Areas of perceived impairment included
memory loss and slowed reaction time. The age of the
subjects at the first exposure to drugs ranged from seven
to 16 years (M = 10.31, SD = 4.49). The duration of drug
use ranged from one to nine years (M = 4.31, SD = 2.28).
Thirteen of the subjects (81.4%) reported a parent or
grandparent with a history of alcohol or drug addiction.
One subject who reported no addiction problem in this group
of relatives was adopted and had no information about the
biological parents. Ten of the 14 subjects with siblings
54
TABLE 1
DEMOGRAPHIC CHARACTERISTICS OF ALL SUBJECTS
Item
Number
Age
M
SD
Grade
M
SD
Sex
Male
Female
Race
White
Nonwhite
Polydrug Users
n
16
16.19
1 .5
9.63
1 .54
8
8
10
5
Neurologically Users
n
15
17.19
3.18
10.07
2.23
12
3
12
4
55
(71.4%) reported a sibling with an addiction problem. Ten
of the subjects had been arrested in connection with their
drug use. These data plus marital history and educational
history of the parents are reported in Table 2.
Medical History of the Polydrug Subjects
Information from medical histories was used in as
sessing the polydrug subjects' neurological background to
determine if exclusion from the study was necessary. Four
of the subjects did have histories of minor head injuries
related to falls and motor vehicle accidents, none of these
injuries had resulted in loss of consciousness. Seven
subjects reported having experienced loss of consciousness
related to drug use and eight indicated having been under
general anesthesia for surgeries such as tonsilectomies.
Eleven subjects indicated that they experienced frequent
headaches and eight reported having been diagnosed with
learning disabilities. These data are reported in Table 3.
Categories of Drugs Used
The frequencies of involvement with differing cat
egories of drugs are presented in Table 4. This group of
adolescents was heavily involved in stimulant and marijuana
use (87.5%). Alcohol use was third highest with 68.8%.
Only two subjects listed no stimulant use. The two
TABLE 2
DEMOGRAPHIC VARIABLES OF THE POLYDRUG GROUP
56
VARIABLE n % VARIABLE n
LIFE SATISFACTION
1 - 3
4 - 6
7 - 1 0
8
SOCIOECONOMIC STATUS
Lower class
Divorced
Widowed
31.3
50.0
18.8
12.5
Middle class 12 75.0
Upper class 2 12.5
PARENTS' MARITAL STATUS
Married 6 37.5
43.8
18.7
QUALITY OF PARENTS' MARRIAGE
Close and Warm 10 62.5
Cold and distant
Angry and Hostile
31.3
6.3
PERCEPTION OF IMPAIRMENT
No
Yes
RELIGIOUS PREFERENCE
Protestant
Catholic
Other
10
EXTENT OF RELIGIOUS FEELING
Strongly
Moderately
Fairly
Mildly
Very Little
Not at all
0
3
4
5
3
0
40.0
60.0
66.7
13.3
20.0
0.0
20.0
26.7
33.3
20.0
0.0
57
TABLE 2 - Cont inued
VARIABLE
MOTHER'S EDUCATION
Less than high school
High school
Some College
College Graduate
Post graduate work
n
0
11
4
0
1
AGE FIRST USED DRUGS
7
8
9
10
12
13
14
15
16
1
1
2
1
6
1
2
1
1
%
0.0
68.8
24.0
0.0
6.3
6.3
6.3
12.5
6.3
37.5
6.3
12.5
6.3
6.3
VARIABLE
FATHER'S EDUCATION
Less than high school
High school
Some college
College graduate
Post graduate work
FAMILY HISTORY OF ALCOHOL DRUG ADDICTION
Father
Mother
Paternal Grandfather
Paternal Grandmother
Maternal Grandfather
Maternal Grandmother
Total subjects with first degree relative with history of addiction
n
3
8
3
2
0
OR
10
1
9
1
8
• 1
13
%
18.8
50.0
18.8
12.5
0.0
62.5
6.3
56.3
6.3
50.0
6.3
81.4
SIBLING HISTORY OF ALCOHOL OR DRUG ADDICTION
Yes 10 62.5
No 37.5
58
TABLE 3 MEDICAL HISTORY QUESTIONNAIRE
QUESTIONS n %
Difficult maternal pregnancy
Premature birth
Subject required postnatal observation
Subject hospitalized before age 6
Febrile convulsions (without other disease) 1
Learning difficulties in school
Traumatic head injury
Posttraumatic amnesia
Nontraumatic unconsciousness
Diagnostic brain tests
History of neurological disease
Epilepsy
Overdose requiring hospitalization
Severe headaches
Frequent muscular weakness
Numbness of extremities
Frequent faintness or dizziness
General anesthesia
1
0
0
2
1
8
4
1
7
3
0
0
4
11
6
5
6
8
6 . 3
0 . 0
0 . 0
1 2 . 5
6 . 3
5 0 . 0
2 5 . 0
6 . 3
4 3 . 8
1 8 . 8
0 . 0
0 . 0
2 5 . 0
6 8 . 8
3 7 . 5
31 . 3
3 7 . 5
8 0 . 0
59
TABLE 4
CATEGORIES OF DRUGS USED
DRUG
Marijuana
Stimulants
Cocaine
Oral stimulants
Intravenous stimulants
Alcohol
Hallucinogens
Depressants
Narcotics
Inhalants
n
14
14
11
7
2
11
4
3
3
2
%
87.5
87.5
68.8
43.8
12.5
68.8
25.0
18.8
18.8
12.5
60
subjects involved in intravenous use of stimulants reported
injections every four to six hours through the day. One
subject, however, reported alcohol as the primary drug of
choice.
Psychological Functioning of Polydrug Subjects
The results of the MMPI provided little information in
assessing the presence or absence of psychopathology in
this population. Only nine of the 16 subjects produced
valid results on the instrument and the hospital was unable
to locate the results on one of these patients. Two
patients could not read well enough to complete the MMPI
and were evaluated by the psychology staff of the hospital
with other measures. The remaining six subjects produced
invalid results. The validity scales suggested that the
invalid results were due to response bias reflecting random
responses, "fake bad" or "fake good" response sets.
Several of the subjects stated during the neuropsych
ological testing that they had been unwilling to respond
appropriately due to the length of the instrument.
Eleven subjects received the Beck Depression Inventory
(M = 12.82, SD = 10.14). The results indicate that the
group fell in the lower end of the mild-moderate range of
depression.
61
Medical History of the Neurologically Impaired Subjects
The neurologically impaired group was made up of 14
victims of closed head injuries, one patient who had
neurosurgery for removal of a tumor. Cognitive data were
provided by the rehabilitation center on 21 patients. On
five of the patients raw data were unavailable and on one
patient the extent of paralysis prevented the admin
istration of nonverbal test items. If more than one
neuropsychological battery had been administered, the most
current results were used. The length of time since the
injury or trauma ranged from one month to 10 years (M =
15.40, SD 29.54).
Clinical Impairment Ratings
The clinical ratings were categorized into six levels
of performance, above average, average, mild deficit,
moderate deficit, severe deficit, and profound deficit
based on assessment of the pattern of ability. Absolute
frequencies and relative percentages for the subjects are
presented in Table 5. These categories were collapsed into
two levels, reflecting functioning within normal limits
(above average, average, and mild deficit) and impaired
functioning (moderate, severe, and profound deficit).
Absolute frequencies and relative percentages of the
unimpaired and impaired ratings are presented in Table 6.
62
TABLE 5
FREQUENCIES OF CLINICAL IMPAIRMENT RATINGS
IMPAIRMENT RATING
Above average
Average
Mild impairment
Moderate impairment
Severe impairment
Profound impairment
POLYDRUG n %
1
5
7
2
1
0
6.2
31 .3
43.8
12.5
6.2
0.0
NEUROLOGICAL n %
1
1
7
4
2
0
6.7
6.7
46.7
26.7
13.2
0.0
TOTAL n %
2
6
14
6
3
0
6.5
19.4
45.2
19.3
9.6
0.0
TABLE 6
FREQUENCIES OF UNIMPAIRED AND IMPAIRED CLINICAL RATINGS
IMPAIRMENT RATING POLYDRUG n %
NEUROLOGICAL n %
TOTAL n %
Unimpai red
Impai red
13 81.2
3 18.8
9 60.0
6 40.0
22 71.0
9 29.0
63
Hypothesis Testing
Hypothesis 1
Hypothesis 1 stated that subjects in a drug addiction
treatment program would score no differently on neuropsych
ological measures of cognitive ability than subjects with
medically identified neurological impairment. The hy
pothesis was tested using a two-tailed t-test procedure
(df=29). The results reflected that the neurological 1y
impaired subjects scored significantly poorer on numerous
measures. The Digit Symbol/Coding subtest of the Wechsler
scales; Trail Making Test, Parts A and B; and the Auditory-
Verbal Learning Test, trials 5 and 6 were significant at
e<.001. Performance I.Q., Arithmetic, and Digit Span of
the Wechsler scales and perseverative responses on the
Wisconsin Card Sort were significant at fi.<.01. The Full
Scale I.Q., the Picture Completion and Block Design
subtests of the Wechsler scales and the recognition trial
of the Auditory Verbal Learning Test were significant at
fi<.05. Complete results are reported in Table 7. The data
are graphically represented in Figure 1.
Discussion of Clinical Significance of Group Means
Clinical review of individual tests and the assignment
of impairment ratings established by normative data is
64
TABLE 7
COMPARISON OF NEUROPSYCHOLOGICAL TEST RESULTS OF POLYDRUG USERS
AND NEUROLOGIC GROUPS
TEST
DRUG (n=16) MEAN
NEUROLOGIC (n=i5) MEAN
WECHSLER INTELLIGENCE SCALE
FULL SCALE IQ 97.06
VERBAL IQ 95.06
PERFORMANCE IQ 100.56
INFORMATION 7.94
COMPREHENSION 9.75
ARITHMETIC 9.00
SIMILARITIES 9.75
DIGIT SPAN 9.75
VOCABULARY 9.12
DIGIT SYMBOL 9.81
PICTURE COMPLETION 10.44
BLOCK DESIGN 10.44
PICTURE ARRANGEMENT 11.13
OBJECT ASSEMBLY 10.13
87.20
87.93
88.07
7.20
8.40
6.93
9.00
7.01
8.13
6.87
8.13
8.47
9.67
8.20
2.04
1.53
2.49
0.82
1.39
2.10
0.69
2.49
0.98
2.99
2.46
1.72
1.38
1.72
.051
.137
.019
.421
.176
.044
.494
.019
.335
.006
.020
.097
.185
.097
TABLE 7 - Continued
65
TEST
DRUG (n=16) MEAN
NEUROLOGIC (n=15) MEAN
WIDE RANGE ACHIEVEMENT TEST-REVISED
READING
SPELLING
ARITHMETIC
91.94
88.81
86.69
93.93
93.07
78.93
-0.34
-0.51
0.94
.735
.613
.353
AUDITORY-VERBAL LEARNING TEST
TRIAL 1
TRIAL 5
TRIAL B
TRIAL 6
TRIAL 5-6*
RECOGNITION TRIAL
COMPLEX FIGURE TEST
COPIED TRIAL
RECALL TRIAL
5.87
12.88
4.94
11.88
1.19
13.94
30.43
17.97
5.13
10.40
3.80
9.07
1.40
12.93
27.17
16.83
1.44
3.03
1.76
2.49
-0.43
2.09
PERCENTAGE RECALLED 58.31 59.73
1.56
0.40
-0.19
.160
.005
.088
.019
.668
.046
.130
.691
.849
* Low score represents better performance
66
TABLE 7 - Cont inued
TEST
WISCONSIN CARD SORTING TEST
CORRECT
ERRORS*
NONPERSEVERATIVE ERRORS*
PERSEVERATIVE ERRORS*
CATEGORIES COMPLETED
TRAIL MAKING TEST
TRAILS A*
TRAILS B*
DRUG (n=16) MEAN
73.06
31.44
14.25
16.06
5.25
22.38
59.38
NEUROLOGIC (11=15) MEAN
79.00
42.33
16.00
24.87
4.60
44.60
107.87
t
-1.59
-1.66
-0.55
-1.74
1.49
-4.62
-3.23
B.
.123
.108
.595
.092
.146
.0001
.003
* Lower score represents better performance
67
1000 T
100 •• e = e =
SCORES
10 ••
••- DRUG GROUP
•o-NEUROLOGIC GROUP
=^^:z^^^—t.~n—^. -o- :S^«^8
H h + H h 1 -M 1 1 1 1 1 FSIQVIOPIO I C A S DS V DSY PC BD PA OA
TESTS
FIGURE 1
COMPARISON OF GROUP MEANS FROM TABLE 7
68
1000 T
100 - 0 = 0 -
SCORES
10 ••
••- DRUG GROUP
•o-NEUROLOGIC GROUP
] - M — I — I I I — I — I I I — I — I — I — I — I — I — I — I — I — h
R S A 1 5 B 6 5/6 R C R PR C E NEPECC A B * * * * * *
VRAT AVLT CFT TESTS
VCS TRAILS
* Low score represents better performance.
FIGURE 1 - Cont inued
69
important in understanding the real significance of the
research findings in addition to the statistical signif
icance. Without the use of available normative data and
cutoff scores for impairment indices, the meaning of the
research findings is less than clear. The most meaningful
review of neuropsychological data is clinical examination
of each individual's test results. This was done in
Hypothesis 2. At this point, however, the discussion will
involve the application of clinical impairment ratings to
the group means. This represents a loss of some descrip
tive information but aids in analysis of the functional
ability suggested for each of the clinically identified
groups. It is important to recall from the Procedures
section that clinical ratings of performance which are
assessed as above average, average, and mildly impaired are
considered within normal limits and that dysfunctional
ability is demonstrated in moderate, severe, and profound
levels of impairment.
Table 8 reports the data for both groups in four
categories. First, there were tasks on which the neuro
logical ly impaired group was statistically different from
the polydrug group and where this also represented a
difference between impaired and unimpaired functioning.
Second, there were tasks on which statistical differences
70
TABLE 8
COMPARISON OF STATISTICAL FINDINGS AND CLINICAL IMPAIRMENT RATINGS ON
INDIVIDUAL TESTS
Signif icant differences-neurological
group impaired
Significant differences-neurological
group unimpaired
Nonsignificant differences-neurological
group impaired
Nonsignificant differences-
both groups impaired
WAIS-A *
WAIS-DS *
WAIS-Dsym *
AVLT-5 *
AVLT-6 *«
TRAILS A *
TRAILS B *
WAIS-PC
AVLT-R
CFT-COPY **
WCS-PE **
WAIS-I *
CFTX *
WRAT-A **
* M i l d impairment
* * Moderate impairment
71
were found but where the scores of both groups fell within
normal limits. Third, there were tests on which there were
not statistical differences but on which clinical ratings
indicated impairment for the neurologic group. The final
category included two items on which there were not statis
tical differences but where the scores of both groups fell
in the impaired range.
Subtest scores on the Wechsler scales are evaluated
against a mean of 10 and a standard deviation of 3
(Wechsler, 1981, 1974). Five subtests showed statistically
significant differences between the two groups. In the
verbal cluster of subtests. Arithmetic and Digit Span both
showed poorer performance (fi<.05) by the neurologic group.
In both instances the performance of the polydrug group was
in the average range while the neurologic group showed a
mild level of impairment on these tasks.
With the nonverbal, perceptual organization subtests.
Digit Symbol/Coding (p<.01) and Picture Completion (p<.05)
showed statistically significant differences favoring the
polydrug group. In each case their functioning was in the
average range. The score of the neurologic group on
Picture Completion fell in the low average range while
their Digit Symbol/Coding scores fell in the low average
range of ability, suggesting a mild level of impairment.
72
The differences in group performance on Trails A and
Trails B describe the polydrug group as functioning in the
average range of ability while the neurologic group showed
mild impairment on this complex task of visual attention
and motor speed. The neurologic group's performance on
these two tests and the subtests of the Wechsler scales.
Arithmetic, Digit Symbol/Coding, and Digit Span (on which
the neurologic group showed statistically significant
differences plus impairment ratings), are consistent with
findings on patients with diffuse brain damage. These
problem areas are commonly found with head injured pop
ulations and are due to difficulty on tasks requiring
sustained attention, mental tracking, and speeded motor
ability (Lezak, 1983).
The final tasks on which the neurologic group showed
both statistically poorer performance and impairment were
trials 5 and 6 of the AVLT. Lezak (1983) suggests that the
pattern of functioning demonstrated by the neurologic group
reflects problems with new learning and retention of infor
mation. While their immediate recall was in the normal
range, along with the polydrug group, their learning across
repeated trials was significantly poorer. Statistical
difference was found on the recognition trial as well but
the neurologic group's score was not in the impaired range.
73
The neurologic group showed moderately impaired scores
on three additional measures where statistically signif
icant differences were not found, computational arithmetic
on the WRAT-R, the copy trial of the CFT, and perseverative
errors on the WCS. The arithmetic score is frequently
impaired in closed head injured populations. The CFT
represents a novel task which requires complex perceptual
organization and planning and is also sensitive to diffuse
brain impairment.
Perseveration is an impairment in cognitive flex
ibility and the capacity to shift response sets as task
requirements change. The normative data on the WCS
(Heaton, 1981) reports a mean of 12.6, SD = 10.2 for per
severati ve errors. Although these data were drawn on an
older population (M = 35.9, SD = 15.3) with high average
Full Scale I. Q. (M = 114.0, SD = 11.7), recent research
(Chelune & Baer, 1986) to establish developmental norms
found that by the age of 10 years children's performance is
comparable to adults. Using the adult norms as the inter
pretive base for the functioning of the two groups in the
current study, the score for the neurologic group on per
severati ve errors indicated moderate impairment.
Two tests showed no differences between the groups but
the scores for both were similar in suggesting lower levels
of functioning. Scaled scores for both groups fell in the
74
low average range for the Information subtest of the
Wechsler scales which assesses general fund of information.
Good performance on this task is contributed to by verbal
comprehension and memory (Kaufmann, 1979). Influences
which affect performance on this subtest include stim
ulation in the child's early environment, school learning,
and intact remote memory, therefore the lower level of
functioning in this area may be accounted for in a variety
of ways. For one person it may be the result of problems
with retrieval of long-term memory while in another it may
be the result of low academic motivation. The small n in
the present study prevented factor analysis of the data to
investigate the factors which may have similarly or dif
ferentially affected the performance of each group.
The other measure on which both groups performed
poorly was the percentage of information recalled on the
CFT. This score was based on Snow (cited in Lezak, 1983)
and was developed to evaluate the memory component of the
task while controlling for the quality of the original
performance on the copy trial. Both groups had difficulty
in this area suggesting a mild level of impairment.
Hypothesis 2
The second hypothesis stated that impairment ratings
based on pattern analysis of each subject's performance
75
would show no significant differences between subjects in
a drug addiction treatment program and neurological 1y im
paired subjects. A t-test procedure was used to test the
hypothesis. There was no significant difference between
the means of the two groups (see Table 9).
76
TABLE 9
T-TEST COMPARISON OF CLINICAL IMPAIRMENT RATINGS
POLYDRUG NEUROLOGICAL (n=16) (n=15) MEAN MEAN
IMPAIRMENT RATINGS 1.81 2.33 -1.43 .163
CHAPTER V
DISCUSSION AND CONCLUSIONS
Summary
The purpose of this study was to examine the cognitive
functioning of adolescents involved in significant abuse of
multiple psychoactive drugs. The literature review re
flected the existence of national concern regarding illegal
drug use with a major focus on the use patterns of adoles
cents. A trend has been noted toward increased social
tolerance of the use of certain substances which have been
popularly labeled as harmless and recreational such as
marijuana and cocaine. Increased attention to the drug
problem in the United States began with an awareness of the
growing drug use by white, middle class teens. While the
popular picture of drug use 20 years ago was heroin ad
diction in the urban ghetto and marijuana use on college
campuses, the mean age of first use by subjects in this
study was 10 years with the earliest exposure at the age of
seven.
A search for causes and effects has covered a broad
spectrum of social, personality, and medical variables.
The observation of the profound effects of intoxication
with various drugs, including the psychotic episodes
associated with amphetamine abuse, led to concern about
77
78
possible longer lasting cognitive impairment as the result
of duration or intensity of drug use. Studies which
investigated cognitive impairment as the result of involve
ment with one drug did not support this hypothesis (Parsons
& Farr, 1981 ).
Investigation of drug taking behavior revealed a trend
toward not only involvement of younger and younger children
but also toward use of multiple substances either in se
quence or simultaneously. The research on the cognitive
functioning of polydrug abusers with a young adult popula
tion did find evidence of mild, diffuse brain dysfunction
(Adams et al. 1975; Grant, Adams, Carlin, Rennick, Judd, &
Schooff, 1978). Earlier research by Bruhn and Maage (1975)
on Danish prison inmates found no differences among four
subject groups: nondrug controls; users of marijuana and
hallucinogens; users of marijuana, hallucinogens, and
stimulants; and users of marijuana, hallucinogens, stim
ulants, and opiates. Grant et al. (1976) suggest that
Bruhn and Maage's lack of identification of cognitive
dysfunction may have been the result of their analysis of
the data on a test by test basis rather than using a
clinical analysis of the pattern of individual performance
and overall impairment ratings. The most comprehensive of
the studies on young adults involved with polydrug use
(Grant, Adams, Carlin, Rennick, Judd, & Schooff, 1978)
79
found that duration and intensity of involvement with
central nervous system depressants and opiates represented
the greatest risk to the integrity of cognitive func
tioning. These results may also explain the discrepancy
with the Danish study since depressants and opiates were
not heavily represented in that subject population.
Based on these findings, the relevant question in this
study was whether, in addition to academic and social
problems, adolescents involved in polydrug use experienced
impairment of cognitive ability. The study was a
comparison of two subject groups, adolescents with
multiple-drug use histories and adolescents with a history
of neurological trauma. Limitations on research design
included the lack of random assignment. The polydrug
adolescents were an intact group of inpatients at a private
psychiatric facility. They were being treated in an
adolescent addictive disease unit. The neurologically
impaired group was matched for age to the drug group.
These subjects had been tested using a modification of the
Halstead-Reitan battery in the three years previous to the
study. They were patients evaluated in a rehabilitation
program in the same community as the psychiatric hospital.
Their evaluation was part of a routine medical follow-up of
their injury. Fourteen of the subjects had experienced
closed head injuries most commonly related to motor vehicle
80
accidents. One of the subjects had had surgery to remove a
brain tumor. The polydrug subjects were tested with the
same neuropsychological battery. They additionally com
pleted a medical history, sociodemographic data, and
personality assessment. The MMPI and BDI were administered
and scored by the hospital. Each hypothesis was tested
with a t-test procedure. Statistically significant results
favoring the polydrug subjects were found for 10 individual
tests. In the 23 remaining tests no differences were found
between the neurologically impaired and the polydrug
groups. On overall impairment ratings no difference was
found between the two groups.
Discussion of the Study
This study described the cognitive functioning of
adolescent polydrug abusers. It was stated that the
results of neuropsychological assessment of an adolescent
polydrug group would show no significant differences from a
group of adolescents who were neurologically impaired
therefore suggesting the existence of mild, diffuse im
pairment related to polydrug use. The comparisons of
performance were made on each assessment procedure and on
clinical analysis of overall ability. Although the results
of the clinical analysis indicated no difference between
the groups, the explanation for the similarity between them
81
was that both groups were functioning within the lower
range of normal limits. Possible reasons for the results
are:
1. Traumatically head injured adolescents involved in
an outpatient treatment program represent a high level of
adjustment in this population and the recovery of cognitive
ability in some patients approaches normal limits with
recovery times averaging more than one year.
2. Cognitive impairment related to the extent and
intensity of drug involvement by this youthful a population
may not be reflected in neuropsychological performance.
3. Cognitive impairment from stimulant use, preferred
by these subjects, may not be reflected in performance on
the individual procedures used in this battery.
4. The mild level of cognitive impairment suggested
by the overall clinical rating of the polydrug subjects may
be descriptive of a group of adolescents who are vulnerable
to involvement in multiple-drug use.
An important question in understanding the results of
an assessment of cognitive functioning is premorbid
ability. In this study no measure of ability prior to the
onset of drug involvement or neurological trauma was
available. Measures of verbal ability which reflect old,
overlearned skills are typically felt to be the most
resistant to the debilitating effects of diffuse brain
82
damage. This resistance is demonstrated in the studies on
adult alcoholics (Parsons & Farr, 1981). Using the
Vocabulary subtest of the Wechsler scales and the oral
reading subtest of the WRAT-R as benchmarks of premorbid
ability it appears that the functioning of both groups
could be described as falling in the lower end of the
average range of ability. Grant et al. (1976) state their
opinion that it was improbable that the deficits which were
observed in their study of young adult polydrug abusers
could have reflected premorbid cognitive ability but they
had no way to control for this in their study. Related
studies on adult alcoholics have explored the possibility
of preexisting lower levels of functioning as an
explanation for the observed deficits in this population.
De Obaldia et al. (1983) studied a group of 55 men admitted
to a Veterans Administration alcohol treatment program and
found that the poorest cognitive functioning was demon
strated by the quartile of the group reporting the most
childhood symptoms related to hyperactivity and minimal
brain dysfunction. Tarter and Alterman (1984) state.
Since the majority of deficits demonstrated in alcoholics are on tasks that involve sustained attention . . . there could be an additive effect of antecedent impairments and alcohol consumption to produce neuropsychological deficits in alcoholics, (p. 3)
Lewis and Hordan (1986) review findings which link phen-
cyclidine (POP) abusers with previous histories of learning
83
disabilities (LD) and learning disabilities with juvenile
delinquency (JD) which is frequently associated with drug
abuse. They state.
The LD-JD hypothesis derives from observation that LD is estimated to be present in 50 percent to 80 percent of the JD population, compared to estimates of LD's presence in 8 percent to 12 percent of the normal-IQ school-age population at large, (p. 192)
Despite the lack of clinical findings of cognitive impair
ment in the current study, it is not possible to state
whether the polydrug subjects' abilities were what they
would have been in the absence of drug use.
The polydrug group was statistically superior to the
neurologically impaired group on 10 of the 33 assessment
scores, 30 tests of specific ability and three composite
intelligence scores. On only two of the tasks did the
polydrug group's performance indicate mild levels of im
pairment when compared to clinical ratings. On the 12
items on which the neurologic group's performance suggested
impairment, seven of them were mild (within normal limits)
and five were moderate. Despite the fact that the compar
ison of group means comes out strongly favoring the
polydrug group, the clinical assessment of each individ
ual's performance analyzed in Hypothesis 2 showed no
difference between the groups. This finding could result
from either good performance by the neurologic group or
poor performance by the drug group. Seven subjects from
84
each group received overall impairment ratings suggesting
low average cognitive functioning (mild impairment).
Although this category falls within normal limits it is at
the lower end of this range. Three of the polydrug
subjects and six of the neurologic group showed ability
suggesting more than mild deficits. It is important to
recall that the clinical pattern analysis allows for
ratings of impairment based on relative strengths and
weakness so that an average Vocabulary score on the WAIS-R
might represent impaired functioning if is was produced by
an individual with a postgraduate degree in English. This
means that a clinical impairment rating might not con
tribute to a lowered group mean. Although the functioning
of both groups suggests lower levels of average ability
this rating falls within normal limits and therefore it
appears more likely that the statistical similarity between
the groups is the result of the relatively good functioning
of the neurologically impaired group than significant im
pairment of the polydrug subjects.
One explanation for the apparently intact cognitive
functioning of the polydrug group may relate to the drug
category favored by the adolescents in the study. The
drugs of choice for the adolescent group in the present
study were stimulants and marijuana with a variety of other
drugs in combination. Only two subjects listed no
85
stimulant use. This is consistent with other findings
involving this age group (Kirby & Berry, 1975). The
findings of this study are consistent with those of Grant,
Adams, Carlin, Rennick, Judd, and Schooff (1978) in
suggesting
That heavy, persistent amphetamine use is not related to neuropsychological impairment in most youthful users, although a few persons might indeed be at risk for idiosyncratic reasons (e.g., preexisting hypertension, vasculitis, or allergic diathesis) yet to be determined, (p. 1071 )
This conclusion must be cautionary because of the small
sample size and the absence of a normal group for com
parison.
The lack of interpretable findings regarding person
ality functioning of the adolescents in the drug treatment
program was a disappointment. Little data were available
on psychological functioning due to invalid results on six
of the MMPI's and no administration of this instrument due
to the poor reading level of two of the subjects. In a
study of the personality correlates of polydrugs abusers,
Kilpatrick et al. (1976) describe a group of 17 males, mean
age 24.59 years, as emotionally labile and overresponsive
to stimuli. They were found to be higher on measures of
state anxiety but not trait anxiety. The authors state,
Neurotocism and extraversion scores considered together and compared with Eysenck's norms (1968) categorize the polydrug users as high on both neuroticism and extraversion, which Eysenck
86
reports to be characteristic of under-socialized psychopaths, (p. 315)
Kilpatrick's group of young adults was also found to be
higher on sensation-seeking than controls. Despite
inadequate data from the MMPI, some evidence exists for
undersocialized features in the functioning of the
adolescents in the current study. Using the diagnosis of
conduct disorder under the DSM III criteria, elevation of
Psychopathic Deviance (Scale 4) on valid MMPI profiles, and
arrests as measures of social deviance, only two polydrug
subjects did not meet this criteria. The same issue,
however, can be raised with the adolescent head injured
group. Recent studies have suggested that this population
was involved in more risk-taking behavior prior to their
accidents than their peers (Lezak, 1983; Rutter, 1981).
They are described as "impulsive, overactive youngsters,
who by nature are more inclined to participate in dangerous
activities" (Begali, 1987). Responses to the BDI suggest a
moderate level of depression in the polydrug subjects.
Some of the depressive features which these adolescents
reported may have been affected by their recent hospital
izations in addition to more chronic concerns.
Whether polydrug abuse by adolescents results in
cognitive impairment is undetermined by this study. It
does appear that polydrug abuse which emphasizes stimulant
use was not related to moderate to severe brain dysfunction
87
in the present group. Further research is needed to
resolve this question and to investigate the problem of
whether such impairment would result from drug use or if
the drug use could be subsequent to and associated with
minimal brain deficits and therefore provide a predictor of
vulnerability for drug involvement. The importance of this
question is twofold. First, if mild cognitive dysfunction
somehow, undoubtedly in combination with other variables,
contributes to involvement in drug use then prevention
strategies should focus on this population. Speaking of
this population. Grant et al (1978b) state that "It may be
necessary to educate persons with such subtle disorders
regarding their greater vulnerability to polydrug-induced
impairment (p. 183)." The second part of this issue in
volves the special therapeutic needs of a population with
minimal brain dysfunction.
Summary of Results
The cognitive effects of polydrug abuse by adolescents
have not been studied previously and the lack of impairment
findings on individual measurement procedures in this
research cannot be taken to indicate that neurological
ability is not affected by multiple drug use. Three issues
may be especially relevant in understanding the cognitive
functioning demonstrated by the polydrug subjects of this
88
study. First, this study consisted of middle class
subjects. Stimulating home environments are highly cor
related with the development of good verbal ability. Good
verbal skills are notoriously resistant to the effects of
mild diffuse neurological dysfunction. Second, the poly
drug subjects of this study fit the criteria for drug
addiction according to the DSM III but within this frame
work the duration and intensity of their drug use was quite
variable. One subject was in a third treatment program,
had extensive scars as the result of intravenous stimulant
and opiate use, began using drugs at age nine, and was on
probation for felony criminal charges related to drug use.
The opposite end of the spectrum in this group was repre
sented by a 15-year-old with a three-year history of abuse
involving marijuana and alcohol. If the number of the
subjects in the study had been large enough, the extent and
intensity of drug use could have been compared with overall
clinical impairment ratings. The third issue, which has
been raised earlier, is the preference in this study for
use of stimulants and the lack of research support for
evidence of deficits in cognitive ability in any age group
in which stimulant use predominated.
89
Implications for Further Research
Future research in this area would need to consider
several issues which arose during this study. A larger n
would be important in increasing the power of the statis
tical tests and to provide data for exploration of
variables related to drug use categories. Availability of
a premorbid measure of functioning such as standardized
academic achievement scores would be valuable in inter
preting the results as would any reliable indicator of
previously established learning disability or minimal brain
dysfunction. Inclusion of a group of normal subjects would
assist in more clearly interpreting the results of the
cognitive functioning of the polydrug group.
This is an important area of study. One which in
volves the identification of cognitive ability in polydrug
abusing adolescents. It involves the investigation of
cognitive factors as etiologic and contributory or as
effects of involvement with drug abuse. Research should
also be directed toward development of appropriate pre
ventive and treatment interventions for adolescents with
cognitive impairment. Grant, Adams, Carlin, Rennick, Judd,
and Schooff (1978) acknowledge this need and recommend
avoiding therapies emphasizing intense emotional arousal
and insight in patients with brain dysfunction.
90
Implications for the Professional
The results of this study indicate that 10 of the
subjects in an adolescent polydrug treatment program were
identified to be functioning at or below the mildly
impaired, low average, range of cognitive ability. This
finding was based on the clinical analysis of individual
patterns of performance of each subject. Whether this
represents an effect, a cause, or a correlation to their
drug abuse it suggests that neuropsychological assessment
of this population can contribute to an understanding of
the patient's functional ability which has great meaning in
terms of effective treatment. If problems are individually
evident in attentional abilities or problem solving, ther
apeutic interventions must respond to a need for repetition
of important material or assistance with processing treat
ment information. Lewis and Hordan (1986) suggest that the
high recidivism rate in their population of POP abusers
could be primarily accounted for by treatment personnel's
lack of information about and accommodation of patients'
cognitive ability. In the absence of any type of im
pairment, these are teenagers with significant adaptive
problems and for those who additionally have cognitive
deficits, identification of these and accommodation of the
treatment plan is necessary. The Lewis and Hordan (1986)
findings of impaired verbal concept formation associated
91
with POP abuse suggests that verbal therapies in which most
counselors are trained places the success or failure of the
patient on an area of relative cognitive weakness.
An additional finding is suggested by the outcome of
this study. The response bias to the MMPI questionnaire by
the polydrug subjects was disappointing. Archer (1987)
states that
For the oppositional and angry adolescent, the MMPI may present a welcomed opportunity to display noncooperation by responding in the slowest and most inappropriate fashion to each item. (p. 34)
This finding is supported by the research of Newmark and
Thibodeau (1979) on administration of the MMPI to adoles
cents in inpatient treatment settings. Modifying the
presentation of this instrument might be useful in
obtaining valid and therefore interpretable results.
Perhaps an explanation of the validity scales and their
ability to detect a bias in responding would be sufficient
to produce an appropriate test-taking attitude. Other
options would be to tie appropriate completion of the test
to some aspect of the treatment program, to substitute
another instrument or form of personality, or to delay the
administration until the patient had developed a minimal
commitment to the treatment program. Although this would
result in the loss of data regarding initial attitudes,
information regarding the more enduring aspects of
92
personality functioning would not be lost and would be
available on more patients.
Interestingly all of the subjects approached for
inclusion in the polydrug group volunteered. Although
there was occasional manipulation when a subject agreed to
a time for the testing and at the last minute would
reschedule in favor of a basketball game, the general
attitude was cooperative. This may have been due to the
novelty of the type of testing included in this battery and
the comraderie which developed among the patients who had
completed the testing, another example of the adolescent
vulnerability to peer pressure. Nevertheless, the coopera
tion of the polydrug subjects suggests their amenability to
this type of investigation.
Conclusions
It would be inappropriate to generalize from the
results of this study due to the small sample size and the
methodological limitations. This study does not compare
the ability of the polydrug group to a normal control of
age-matched peers. A striking finding, however, was that
the overall impairment ratings based on clinical pattern
analysis of individual performance suggested mild to severe
neurological impairment for two-thirds of the polydrug
group. The research on amphetamine use by adults has not
93
found abuse of stimulants to result in permanent cognitive
impairment. This provokes the thought that perhaps the
cognitive ability of the polydrug subjects of this study
represents a premorbid level of functioning rather than an
effect of drug use. The finding that 81.4% of these poly
drug using adolescents have a first degree relative with a
history of alcohol or drug addiction suggests that consid
eration of the research supporting genetic transmission of
alcohol addiction could be germaine to an understanding of
the risk factors for polydrug users. Although alcohol was
not the drug of choice for the subjects of this study it
may be that the availability and increased social accept
ance of drug use has resulted in polydrug involvement in
teenagers who in the past would only have had access to
alcohol.
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APPENDIX A
MEDICAL HISTORY QUESTIONNAIRE
100
101
MEDICAL HISTORY QUESTIONNAIRE
Screening Items Yes No Not Sure
Difficult maternal pregnancy
Premature birth
Required postnatal observation
Hospitalized before age 6
Febrile convulsions
Learning difficulties in school
Traumatic head injury
Posttraumatic amnesia
Nontraumatic unconsciousness
Diagnostic brain tests
History of brain disease
Epilepsy
Overdose requiring hospitalization
Severe headaches
Frequent muscular weakness
Numbness of extremities
Frequent faintness or dizziness
General anesthesia
APPENDIX B
DEMOGRAPHIC QUESTIONNAIRE
102
103
DEMOGRAPHIC QUESTIONNAIRE
1. On a scale of 1 to 10 how satisfied are you with your life right now? One represents least satisfied and 10 most satisfied.
2. How would you describe your family?
a. Lower class b. Middle class c. Upper class
3. What is your parents marital status?
a. Married b. Divored c. Widowed
4. How would you describe the quality of your parents' marriage?
a. Close and warm b. Cold and distant c. Angry and hostile
5. Do you feel that you have experienced brain impairment as the result of your drug use?
6. What is your religious preference?
7. To what extent do you consider yourself religious?
a. Strongly b. Moderately c. Fairly d. Mildly e. Very Little f. Not at all
8. What was the highest grade in school completed by your mother?
9. What was the highest grade in school completed by your father?
10. At what age did you first use drugs?
11.
104
Do any of the following members of your family have history of alcohol or drug addiction?
a. Father b. Mother c. Paternal d. Paternal e. Maternal f. Maternal g. Siblings
Grandfather Grandmother Grandfather Grandmother
APPENDIX C
GLOSSARY
105
106
GLOSSARY
Amnestic - Cognitive problems dealing with recent and remote memory.
Focal - The focal effects of brain damage refer to predictable and circumscribed intellectual losses resulting from injury to a specific cite.
Impairment - The difference between a person's present level of functioning and the expected level of original ability.
Polydrug - Simultaneous or sequential use of multiple categories of drugs.
Perseveration - Meaningless repetition of a previous response prohibiting appropriate shifting of responses as task requirements change.
Premorbid - Premorbid ability is the intellectual potential or capacity which was present prior to disease, developmental anomalies, emotional disturbance, or any condition that has impaired the expression of these abi1ities.