the delirium rating scale (drs)

Psychosomatics 40:3, May-June 1999 193

The Delirium Rating ScaleIts Use In Consultation-Liaison Research

PAULA T. TRZEPACZ , M.D.

In addition to diagnostic criteria, delirium research requires standardized instruments to measuresymptoms. This article reviews the literature about the Delirium Rating Scale (DRS), the mostwidely used scale to assess delirium that has been translated into at least seven other languages.The DRS has 10 items and is clinician-rated, but 7- or 8-item subscale adaptations have beenused for repeated measurements. It has high scale characteristics, including internal consistency,validity, specificity, sensitivity and interrater reliability. The DRS distinguishes delirious from de-mented, schizophrenic, and depressed patients and is more accurate than cognitive tests in identi-fying delirium. Scores are sensitive to treatment of delirium. Principal components analyses findone underlying dimension that can be subdivided into two or three components. The DRS hasbeen used in studies of phenomenology, physiology, treatment, outcome, and at-risk populations.Tables summarize details from various studies. The DRS is used clinically and in research. It iscurrently being revised to enhance its use in phenomenologic and treatment research.

(Psychosomatics 1999; 40:193204)

Received August 26, 1998; revised November 24, 1998; accepted De-cember 4, 1998. From the University of Mississippi Medical School,Jackson, Mississippi. Previously published in similar form in Japanese inNeuro-Psychiatric Review, Vol. 26, 1998, pp. 1631. Address correspon-dence and reprint requests to Dr. Trzepacz, Department of Psychiatry andHuman Behavior, University of Mississippi Medical Center, 2500 NorthState St., Jackson, MS 39216; e-mail: [email protected].

Copyright q 1999 The Academy of Psychosomatic Medicine.

ASSESSMENT OF DELIRIUM

Delirium is a neuropsychiatric syndrome that involves anumber of symptoms, including diffuse cognitive impair-ment, psychosis, sleep-wake cycle disturbance, perceptualdisturbances, thought disorder, language impairment, andmood lability. Symptoms of delirium typically have anacute onset and tend to fluctuate in intensity throughout a24-hour period. Its incidence averages about 18% to 20%of patients admitted to general hospitals, though this figurevaries somewhat depending on the patient population andmethodology of the research.1 Despite its prevalence andassociated morbidity and mortality,1 delirium is under-studied compared with dementias and other psychiatricdisorders. One of the methodological difficulties in study-ing delirium had been a dearth of appropriate symptom-rating scales and lack of diagnostic criteria. DSM-III,DSM-III-R, and DSM-IV diagnostic criteria have beenpublished as various revisions by the American PsychiatricAssociation since 1980 and have been beneficial in that

they list specific inclusion and exclusion criteria for diag-nosing cases of delirium.2,3

Several instruments have been devised for health careprofessionals or laypersons to screen for the presence ofsymptoms of delirium, such as the Confusion AssessmentMethod (CAM)4 and the Delirium Symptom Interview(DSI),5 respectively. The CAM and DSI are reviewed inmore detail elsewhere.6,7 The CAM has four items that rep-resent cardinal symptoms, three of which are required tobe present for a diagnosis of delirium. The CAM was orig-inally reported to have sensitivity ranging from 94% to100% and specificity ranging from 90% to 95%, comparedwith diagnoses made by using DSM-III-R criteria. How-

The Delirium Rating Scale

194 Psychosomatics 40:3, May-June 1999

TABLE 1. Items on the Delirium Rating Scale

1. Temporal onset2. Perceptual disturbances3. Hallucinations4. Delusions5. Psychomotor behavior6. Cognitive status7. Physical disorder8. Sleep-wake cycle disturbance9. Lability of mood

10. Variability of symptoms

ever, a subsequent study8 reported CAM sensitivity to be68% when rated by nurses, compared with diagnoses madeby research physicians who used DSM-III-R criteria (andthe Delirium Rating Scale) to assess medically ill elderlypatients.

There are a few instruments that include a broad rangeof delirium symptoms to detect and rate the severity ofthose symptoms. Three scalesthe Saskatoon DeliriumChecklist,9 the Organic Brain Syndrome Scale,10 and theDelirium Assessment Scale11are checklists that opera-tionalize DSM-III criteria, with items rated on a mild-to-moderate severe continuum. In contrast, three other scalesrate symptoms by using descriptive choices for each item.These are the Delirium Rating Scale,12 the Nurses DeliriumRating Scale,13 and the Memorial Delirium AssessmentScale (MDAS).14 The MDAS is intended for rapid serialratings of delirium severity but does not include items fordiagnosis. When compared with the DRS in 51 deliriouspatients with AIDS or cancer, the MDAS showed a highcorrelation to DRS total scores (r40.88, P,0.0001), whileits individual item correlations with DRS total scoresranged from 0.50 to 0.78.14

The Delirium Rating Scale (DRS) is the most widelyused instrument for rating the severity of delirium withvalidity, high interrater reliability, and substantial sensitiv-ity and specificity. It is used for clinical and research pur-poses not only in the United States, but also in Canada,Europe, South America, and Asia. The DRS has been trans-lated into seven languages other than English. It was trans-lated into French by Darius Razavi in Brussels, MandarinChinese by Chia-Yih Liu in Taipei, Dutch by Herman Snoin Amsterdam, Spanish by A. Bulbena in Barcelona, Italianby Augusto Caraceni in Milan, Swedish by Walter Osikain Karlskoga, and Japanese by Kunihiro Isse in Tokyo. TheDRS also may become available in Portugese and a lan-guage of India (being translated by Mahesh Tilwani in Gu-jarat).

This article reviews the literature involving the DRS,including scale characteristics, analyses of scale items, andstudies on treatment, phenomenology, physiology, and out-come of delirium.

DELIRIUM RATING SCALE

Scale Description

The DRS is a 10-item rating scale (see Table 1) in-tended to be completed by a clinician with psychiatrictraining to more sensitively detect the range of psychiatric

symptoms assessed by the scale. Thus, it most often hasbeen used by psychiatrists and research-trained psychiatricor geriatric clinicians. Each item has specific descriptorsthat can be scored from 0 to a maximum either of 2, 3, or4 points, depending on the item. The sum of all item scorescomprises the total DRS score; the maximum possiblescore is 32 points.

It is suggested that symptoms be rated over a 24-hourperiod because of the fluctuating nature of delirium symp-tom severity and to better detect the disruption of the sleep-wake cycle. With some adaptation, the DRS can be ratedfor partial days. However, because the inherent waxing andwaning of symptom severity might falsely lead the rater toconclude clinical improvement or worsening, smaller timeintervals for repeated ratings must be chosen carefully. Inaddition, certain items are difficult to rate during repeatedadministrations. This includes Item #1, temporal onset ofsymptoms, because a judgment is required to determineat what point during an episode to no longer take into ac-count the characteristics of the initial symptom onset. Forexample, when the episode no longer meets DSM criteriafor delirium, the rater might decide to rate Item #1 as 0at that time. Though this possibility poses a rating di-lemma, Item #1 does capture an important phenomenologiccharacteristic of delirium, which contributes to the validityof the scale and helps to differentiate delirium from otherpsychiatric disorders, including dementia. The same issueapplies to the rating of Item #7, which requires a decisionabout when the underlying medical cause of delirium is nolonger relevant. (A revised form of the DRS that is cur-rently under study will address this problem for repeatedratings.) In addition, some researchers have used partialscale ratings when the DRS is used serially. For repeatedmeasures in a treatment study, Uchiyama et al.15 used asubscale of 7 items (excluding temporal onset, physicaldisorder, and fluctuation of symptoms) that was used afterthe initial ratings. Nakamura et al.16 used an 8-item scale(excluding temporal onset and physical disorder) for re-

Trzepacz


peated measurements in a drug treatment study of delirium.Koolhoven et al.17 used a 7-item modified scale as a symp-tom checklist in an observational study by excluding twoitems (temporal onset and physical disorder) and compress-ing perceptual disturbances and hallucinations into oneitem.

The DRS was devised intentionally to reflect a broaderrange of symptoms of delirium than was assessable by us-ing only cognitive tests such as the Mini-Mental StateExam (MMSE). Bedside cognitive tests alone cannot dis-tinguish between different disorders that involve cognitiveimpairment, for example, delirium and dementia. Instead,assessment of a broad range of symptoms is necessary todistinguish delirium from other cognitive disorders. Thisincludes assessing the severity and type of cognitive defi-cits, because different dementias affect different cognitivefunctions at different stages of the illness (e.g., frontal lobedementias vs. Alzheimers dementia). One type of demen-tia Lewy body dementia has significant overlap withdelirium in its presentation, as does Alzheimers dementiaat its end-stage.

It was originally intended that the DRS be supple-mented by whatever cognitive tests that the rater chooses.The DRS has only one cognitive status item (Item #6) anddoes not rate separate items for different components ofcognition (e.g., attention, memory, orientation). Thoughthis allows relatively more emphasis of noncognitivesymptoms, it may make the DRS less useful for phenom-enological studies or repeated measurements.

Scale Attributes

The DRS has been studied in different settings andfound to have very good construct validity based on mul-tiple lines of evidence, which are detailed in Table 2 andTable 3 and in later sections of this article. These includecomparisons to expert diagnoses by using DSM criteria,differences in DRS scores compared with other patientgroups, differences in DRS scores following standard de-lirium treatment when patients no longer meet DSM cri-teria for delirium, and correlations with ratings on otherscales (e.g., Brief Psychiatric Rating Scale [BPRS], cog-nitive tests, and global ratings) that assess some deliriumsymptoms.

The DRS has excellent internal consistency, with aCronbachs alpha score of 0.90 in a study of elderly pa-tients.18 In addition, principal components analysis of DRSscores has shown that it has one major underlying dimen-sion,19,20 supporting that it is measuring one overall con-

struct. Moekken analysis performed by van der Mast21 inpostcardiotomy patients revealed a coefficient of reliabilityRho P4 0.81, HI item coefficients that were each .0.40,and the H coefficient of scalability40.61, indicating astrong hierarchical nature of the items of the scale. Theseauthors felt that the results of their Moekken analysis im-plicated that each DRS item was related to the severity ofdelirium and, therefore, that the DRS can function as asymptom severity scale.

Correlations of DRS items to other items have beendone in two studies. In 20 general medically ill deliriouspatients, the cognitive item correlated highly with hallu-cinations (r40.44, P40.027); delusions (r40.63,P40.001); psychomotor behavior (r40.48, P40.017);sleep-wake cycle disturbance (r40.56, P40.0005); andlability of mood (r40.60, P40.003) in one study.12 Thecognitive item correlated highly with psychomotor behav-ior (r40.41, P40.014), sleep-wake cycle disturbance(r40.39, P40.02) and variability of symptoms (r40.38,P40.023) in a study of 36 delirious postcardiotomy pa-tients.21 In both studies, temporal onset of symptoms cor-related significantly with perceptual disturbances (r40.44,P40.028 in the former and r40.53, P40.001 in the lat-ter).

There are a few studies about DRS items. One studyfound individual DRS item scores to be significantly higherin delirious than in moderately demented patients for allitems, except cognitive status, which was similar(P40.022 for hallucinations and P,0.001 for otheritems).19 In a comparison between elderly patients withdelirium and those with both delirium and dementia,20 onlythe cognitive status item differentiated the groups, withmore impairment in the dual diagnosis group. Wada andYamaguchi22 reported that the presence of certain DRSitems predicted the duration of delirium episodes. Meagheret al.23 subgrouped DRS items into subscales for core dis-turbances representing either cognitive impairment or be-havioral management problems in a study of environmen-tal manipulation as a delirium treatment.

Because the DRS does not rely on only cognitiveitems, it is has been found to be superior to cognitive testsalone in distinguishing delirium from other disorders. TheDRS, unlike the MMSE, distinguished delirium from de-mentia patients, and the DRS also distinguished deliriumfrom schizophrenia patients, unlike the TrailmakingTests.12 Receiver operating characteristic curve analysescomparing the DRS with the MMSE in a study of 104elderly delirious patients found the DRS to be significantlymore accurate than the MMSE in classifying delirium (area



TABL

E2.

Del

iriu

mR

atin

gSc

ale

(DRS

)cha

ract

erist

icsi

nst

udie

s

Stud

ySa

mpl

eD

RS

Rat

ers

Inte

rrat

erR

elia

bilit

ySe

nsiti

vity

an

dSp

ecifi

city

Oth

erTr

zepa

czet

al.

(1998

).G

eria

tric

psyc

hiat

ryin

patie

nts,

n4

61,f

rom

843

con

secu

tive

adm

issio

ns,m

ean

age5

SD:

745

8

5tr

aine

dre

sear

chas

sista

nts

(nonp

hysic

ians)

who

wer

e

blin

dto

diag

nose

s

Intra

clas

scorr

elat

ion

coef

ficie

nt(IC

C)ra

nge

durin

gst

udy

perio

dw

as0.

59to

0.75

DSM

-III-R

crite

ria;4

5/56

patie

nts

had

abno

rmal

EEG

s;co

mpa

red

delir

ium

with

delir

ious

-dem

ente

dpa

tient

sM

eagh

eret

al.

(1996

).Co

nsec

utiv

eC-

Lpa

tient

sin

gene

ralh

ospi

tali

nIr

elan

d,n4

46,m

ean

age4

60

Clin

icia

nsIC

D-1

0de

liriu

mcr

iteria

;DR

Sbr

oken

dow

nin

totw

osu

bsca

les:

beha

vior

alan

dco

gniti

vedi

sturb

ance

sR

ockw

ood

etal

.(19

96).

Ger

iatri

cps

ychi

atry

con

sults

(n434

)an

dge

riatri

cm

edic

ine

inpa

tient

s(n4

70)i

nge

nera

lho

spita

lin

Nov

aSc

otia

Atte

ndin

gph

ysic

ians

plus

inde

pend

ently

rate

dD

RS

bya

resid

entp

hysic

ian

inps

ychi

atry

or

geria

tric

med

icin

e

ICC4

0.91

Cuto

ffsc

ore

410

:Se

nsiti

vity

40.

82Sp

ecifi

city

40.

94Cu

toff

score

47.

5:Se

nsiti

vity

40.

90Sp

ecifi

city

40.

82

DSM

-III-R

crite

ria;c

om

pare

dde

liriu

mto

dem

entia

,oth

erps

ychi

atric

,and

aco

gniti

vely

unim

paire

dgr

oup;

RO

Ccu

rve

anal

ysis

show

edD

RS

signi

fican

cehi

gher

than

for

MM

SEas

ate

stfo

rdel

irium

;Cr

onba

chs

alph

a40.

90as

a

test

ofi

nter

nalc

onsis

tenc

yR

osen

etal

.(19

94)

Cons

ecut

ive

geria

tric

psyc

hiat

ryin

patie

nts(

n4

791),

Mea

n5SD

age4

735

9,3

grou

psst

udie

d:de

liriu

m(n4

70),

org

anic

men

tal

diso

rder

with

outd

eliri

um(n4

291),

no

no

rgan

icdi

agno

sis(n4

430)

Trai

ned

rese

arch

clin

icia

ns(no

nphy

scian

s)w

how

ere

blin

dto

final

diag

nosis

ICC4

0.69

to0.

99(ra

ngeo

ver

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ype

riod)

on

DR

S,B

PRS,

and

MM

SE

Atc

uto

ff$

10:

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itivi

ty4

0.94

Spec

ifici

ty4

0.82

,Pr

edic

tive

posit

ives

433

%,

pred

ictiv

eneg

ativ

es4

99%

DSM

-III-R

crite

ria;p

sych

osis

and

cogn

itive

impa

irmen

tsy

mpt

oms

false

lyel

evat

edD

RS

score

sin

org

anic

men

tal

diso

rder

grou

p;only

4/70

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ious

wer

efa

lseneg

ativ

es;

32%

wer

efa

lsepo

sitiv

esin

org

anic

men

tald

isord

ergr

oup

butt

hese

case

sw

ere

more

likel

yto

have

abno

rmal

EEG

and

low

erM

MSE

score

s

Trze

pacz

etal

.(19

88)

Gen

eral

and

psyc

hiat

richo

spita

lpa

tient

s;de

lirio

us(n4

20),

dem

ente

d(n4

9),sc

hizo

phre

nic

(n49),

oth

erm

edic

ally

ill(n4

9);m

ean5

SDag

eo

fdel

iriou

s:59

517

and

ofd

emen

ted:

785

4

Atte

ndin

gps

ychi

atris

tsan

dps

ychi

atric

resid

ents

ICC

40.

97D

SM-II

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;box

plot

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no

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lap

inD

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score

sbe

twee

ngr

oups

;DR

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orr

elat

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ithag

e;D

RS

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MSE

(r41

0.43

,P4

0.03

3)an

dTr

ailm

akin

gTe

stpa

rtB

(r40.

66,P

40.

007)

inde

liriu

mU

chiy

ama

etal

.(19

96)

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ecut

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rlyin

gene

ral

hosp

italg

eria

tric

psyc

hiat

ryu

nit

(n462

),m

ean

age4

80.7

year

s,50

had

hype

ract

ive

delir

ium

and

12ha

dhy

poac

tive

delir

ium

;25

had

pree

xisti

ngde

men

tia

Use

dD

SM-IV

crite

riaan

da

7-ite

mD

RS

forr

epea

ted

mea

sure

men

tsin

atr

eatm

ent

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yaf

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itial

ratin

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selin

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score

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dnot

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reat

men

tre

spon

siven

ess

Trzepacz


Van

derM

ast

(1994

)Co

nsec

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epo

st-ca

rdio

tom

ypa

-tie

nts

(n429

6)in

gene

ralh

ospi

-ta

lin

the

Net

herla

nds;

delir

ious

(n436

)an

dn

on

-del

iriou

s(n4

256);

mea

n5

SDag

e:63

511

(rang

e:20

83)

One

oft

wo

rese

arch

psyc

hiat

rists

DSM

-III-R

crite

ria;D

RS

on

day

3an

don

m

axim

um

day;

high

disc

rimin

anta

bilit

y;M

oekk

enan

alys

issh

owed

heira

rchi

cal

stru

ctur

eofD

RS

Roc

kwoo

det

al.

(1993

)Co

nsec

utiv

eac

ute

geria

tric

ad-

miss

ions

(n416

8)to

med

ical

war

dsin

Nov

aSc

otia

,del

irium

(n448

),th

ough

half

also

de-

men

ted;

mea

n5

SDag

e:79

58

Atte

ndin

gph

ysic

ians

and

inha

lfofc

ases

are

sear

chph

ysic

ian

did

anin

depe

nden

tsec

ond

DR

S

Inte

rrat

erR

elia

bilit

y(IR

)40.

86D

SM-II

I-Ran

dD

SM-II

Icrit

eria

Nak

amur

aet

al.

(1994

)G

ener

alho

spita

lpsy

chia

tric

re-

ferra

ls(n4

76);

alco

holw

ith-

draw

alex

clud

ed;m

ean5

SDag

e:69

.55

12.4

4ps

ychi

atris

tsCl

inic

aldi

agno

sisofd

eliri

um;

modi

fied

DR

Suse

d(w

ithou

t2ite

ms)

forr

epea

ted

mea

sure

s

over

7da

ysfo

rdru

gtr

eatm

ent

stud

yG

olds

tein

and

Fo-

gel(

1993

)Po

stop

elde

rlyte

sted

atD

ay3,

n4

82;e

xcl

uded

dem

ente

dpa

-tie

nts

and

thos

ew

ithM

MSE

,23

preo

pera

tivel

y;m

ean5

SDag

e:67

57

Res

earc

has

sista

nts(

traine

dnurs

esan

dps

ycho

logi

sts)

IR4

0.90

under the curve40.87 for the DRS, area test411.93,P40.03).18

Though the DRS measures more than just cognition,DRS scores have correlated with cognitive test scores ingeneral hospital samples. The DRS correlated with theMMSE scores (r410.43, P40.033) and with Trailmak-ing Test part B scores (r40.66, P40.007) in 20 deliriouspatients and with the MMSE scores (r410.78, P,0.01)in 104 elderly delirious patients.18 In contrast, in a studyof 61 elderly delirious patients who were admitted to apsychiatric hospital instead of a general hospital, there wasno correlation between the DRS and the MMSE(r40.16).20 However, in that same study, the DRS wassignificantly correlated with the BPRS in delirious(r40.57, P40.017) and delirious-demented patients(r40.35, P4 0.04). This finding suggests possible differ-ences in the presentation of patients whose identified medi-cal morbidity is lower and who are admitted to a psychi-atric hospital instead of a general hospital.

Two studies have compared delirious, demented,schizophrenic, and noncognitively impaired medically illpatients and found little or no overlap in total DRS scoresamong these groups when graphing scores on boxplots.18,20Similarly, a study of postcardiotomy patients found verylittle overlap in DRS scores graphed on boxplots betweenthe delirious and nondelirious patients;21 overlap was at-tributed to a methodological issue in the timing of the rat-ings. By using ROC analysis, Rockwood18 found the DRSto be more accurate than the MMSE in classifying deliriumamong groups of elderly patients with either delirium, de-mentia, or other psychiatric disorders.

Rosen et al.24 studied 791 consecutive geriatric psy-chiatry inpatients who were divided into three studygroups: delirium, dementia/organic mental disorder nototherwise specified, and noncognitively impaired patients.Rosen et al. reported that the DRS had a high predictivenegative value of 99%, but its predictive positive value wasonly 33%, largely related to its difficulty differentiating theother organic mental group from the delirium group due tooverlapping symptoms of psychosis and cognitive impair-ment. There were only 4 out of 70 false-negatives amongthe delirium group, but 94 out of 291 other organic mentaldisorder patients were rated as false-positives when usinga DRS cutoff of $10 points. However, these false-positivesin the other organic group were more likely to have sig-nificant electroencephalogram (EEG) abnormalities, withGrades II and III dysrhythmias, higher BPRS psychosisscores, and lower MMSE scores than the true-negatives inthat group. Abnormal EEGs of that severity are usually



common in delirium and uncommon in dementia until verylate stages, which opens the possibility of misassignmentof patients who may have really been delirium cases andwere not truly false-positive cases. Their DRS ratingswere in the high 8-point range. In addition, differential di-agnosis of organic mental disorders is especially difficultin the elderly. This study used nonphysician DRS raterswhose interrater reliabilities were lower than in other stud-ies that used physicians (for example, in Rockwood et al.,181996).

The DRS generally has high values for sensitivity andspecificity and high interrater reliability (see Table 2). In-terrater reliabilities vary according to who does the ratings.Highest ratings are for psychiatric and geriatric medicalphysicians and range from 0.86 to 0.97. For nonphysicianswho are trained to use the DRS for research purposes, in-terrater reliability ranges from 0.59 to 0.99. Sensitivity andspecificity depends on the cutoff value used for the DRS.In usage of a cutoff score of 10 points, sensitivity has beenreported at 0.94 and 0.82, and specificity at 0.94 and 0.82.In usage of a cutoff score of 7.5 points, sensitivity has beenreported at 0.90 and specificity at 0.82.

Mean DRS scores for delirious patients are consider-ably higher than for demented or other diagnostic groupsof patients in many studies (see Table 3) across a broadrange of ages of adults who have a wide variety of deliriumetiologies, medical and surgical. Mean scores decreasewith treatment of delirium.15,16,2527 Mean DRS scores alsodo not change when treatment is ineffective.15,26 DRSscores can distinguish different motoric presentations ofdelirium, that is, hyperactive and hypoactive subtypes, withmixed presentations having intermediate scores betweenthem.23 Total DRS scores differentiated patients whose de-lirium episodes lasted more or less than 1 week,22 sug-gesting the score has predictive value as an outcome mea-sure.

Factor Analysis of DRS Items

There are three studies of DRS items using principalcomponents analyses to better understand the relationshipbetween items of the scale and whether they reflect one ormore groupings.1921 In two studies, there seems to be asingle underlying dimension consistent with the DRS mea-suring a single construct, that is, the syndrome of delirium.Trzepacz and Dew19 found one strong underlying dimen-sion that could be further subdivided into two componentsafter Varimax rotation, in a study of 20 delirious adults seenin a general hospital. One component was composed of

delusions, psychomotor behavior, cognition, sleep-wakecycle disturbance, and mood lability; the other composedof temporal onset of symptoms, perceptual disturbances,hallucinations, and fluctuation of symptoms. Van derMast21 studied 40 postcardiotomy delirious patients andfound three underlying factors after Varimax rotation:1) temporal onset of symptoms, perceptual disturbances,delusions, and psychomotor behavior; 2) psychomotor be-havior, cognitive dysfunction, sleep-wake cycle distur-bance, and fluctuation of symptoms; and 3) physical dis-order and absence of lability of mood. Van der Mast,however, felt the third was an artifact because the mostseverely physically ill patients were not ratable on themood lability item. Trzepacz et al.20 studied a psychoge-riatric population, comparing delirious with delirious-demented patients, and identified two core factors on theDRS after Varimax rotation. A total of seven DRS itemswere common to both groups, while three items did notcluster similarly (hallucinations, cognition, and fluctuationof symptoms). In addition, these delirious-only patientsfactor structure was remarkably similar to that from a gen-eral hospital delirium sample from a general hospital sam-ple.19 In both of these delirium samples, Factor 1 loadedsleep-wake cycle disturbance, psychomotor behavior, andmood lability, while Factor 2 loaded temporal onset, symp-tom variability, and perceptual disturbances.20 The threeitems that loaded onto Factor 2 have been considered byseveral experts to be highly associated with delirium, sug-gesting that the DRS analyses were detecting informationapplicable to delirium phenomenology.

STUDIES USING THE DRS

In addition to reports about scale characteristics or DRSitem analyses, the DRS has been used in research studiesand as an assessment instrument in at-risk populations.These include studies about phenomenology, physiology,outcome, and treatment.

Phenomenology Studies

Platt et al.27 studied motoric subtypes of 24 hospital-ized delirious AIDS patients by using DSM-III-R criteriaand repeated DRS measurements. All had DRS scores .12points prior to treatment with either haloperidol or chlor-promazine. Nine were considered hyperactive and 11 hy-poactive in presentation based on clinical judgment and ascore of at least .1 point on the DRS psychomotor item.Both the hyperactive and hypoactive groups responded

Trzepacz


within hours of treatment with either antipsychotic drug(even before the underlying medical problems were cor-rected), as evidenced by significant declines in their DRSscores (P,0.001 for each subtype). Platt et al. suggestedthat both motoric subtypes respond equally well to dopa-mine blockade.

Rockwood28 studied the occurrence and duration ofsymptoms in 173 elderly medical inpatients in Camp HillHospital, Nova Scotia. Many had concurrent dementia.DSM-III and DSM-III-R criteria and DRS ratings were ap-plied on admission. Delirious patients mean5standard de-viation (SD) age was 8258 years and mean5SD DRSscore was 1754 points; nondelirious patients mean5SDage was 7958. Rockwood28 found that DSM-III-R hadbetter sensitivity and DSM-III had better specificity in de-lirium diagnosis, compared with a clinical gold standard.In addition, some delirium symptoms were found to persistat discharge after the episode had ended.

Uchiyama et al.15 used the DRS to compare drug re-sponse between hyperactive and hypoactive presentationsof delirium in their study of 62 delirious elderly. The re-searchers found that 80.6% were hyperactive and 19.4%were hypoactive on the basis of clinical observation. Thehyperactive patients responded better to mianserin than didthe hypoactive patients (P,0.05). Medication responsewas defined as improvement on item scores for $4 DRSitems with worsening on #2 items. DRS scores for eachmotoric subtype were not reported.

Meagher et al.23 studied hypoactive, mixed, and hy-peractive subtypes in 46 delirious inpatients. By using In-ternational Classification of Diseases (ICD)-10 criteria andLiptzin and Levkoffs definition of motoric subtypes, theresearchers found significantly higher (P,0.01) DRSscores in hyperactive and lower (P,0.01) scores in hy-poactive than in mixed subtypes (see Table 3). In addition,the hyperactive group required significantly more nursingmanagement interventions (P,0.05) and hypoactive less(P,0.01) than the mixed group. The hyperactive group(93%) also received more psychotropic drugs prior to con-sultation.

Physiology Studies

In a drug treatment study of delirious patients, Naka-mura et al.16 measured plasma-free 4-methoxy-3-hydroxy-phenylethylene glycol (MHPG) and homovanillic acid lev-els. The researchers found a significant reduction in plasmafree-MHPG over time in all delirious patients, regardlessof drug treatment using mianserin, oxypertine, or haloper-

idol. This reduction paralleled a decrease in DRS scores,indicating that reducation in delirium severity was associ-ated with decreased plasma-free MHPG.

Tanaka et al.29 used the DRS in a study of the role ofcerebrospinal fluid (CSF) prostaglandin D2 and E2 levelsin the sleep-wake mechanism of delirium. Seven inpatientsat Tokyo Metropolitan Tama General Hospital (mean age:78.4) who had delirium were compared with 7 age-matched controls (mean age: 74.9) without neurologic orpsychiatric problems. DSM-III-R criteria were used for di-agnosis, and the DRS was used serially. Mean DRSscore424 points. The researchers found that CSF prosta-glandin D2 was significantly higher in the delirious patientsthan in the control subjects.

At-Risk Population Studies

The DRS has been used to assess the presence of de-lirium symptoms in at-risk medical populations. DiMartiniand colleagues30 used the DRS in studies of liver transplantpatients at the University of Pittsburgh Medical Center. Ina comparison of two immunosuppressant drugs, cyclo-sporine A and FK506 (tacrolimus), DRS scores were in thenondelirious range (see Table 3), despite the presence ofneuropsychiatric symptoms known to be associated withtoxicity of these drugs.30 Some patients scored below 24points on the MMSE and above 80 seconds on TrailmakingTest part B. This finding suggests some specificity for theDRS regarding the symptoms it detects. In a randomizedcomparison study of FK506 and cyclosporine A, DiMartiniet al.31 described 31 orthotopic liver transplant patientscross-sectionally 1 week postop (mean5SD age: 4059).DRS scores were in the nondelirious range in both druggroups, with only 2 patients scoring above 12 points (19and 22 points), both in the FK506 group. MMSE scoreswere also in the unimpaired range, though some patientshad impairment on the Trailmaking tests.

Goldstein and Fogel32 used the DRS to assess 82 el-derly patients (mean5SD age: 6757) undergoing electivesurgery at State University of New York, Buffalo, Schoolof Medicine, as part of a longitudinal study. Patients whoseMMSE score was ,23 points preoperatively were ex-cluded from the study. Mean5SD DRS score at Day 3postop was 2.1752.73 (range: 016) and only one pa-tients DRS score was in the delirium range. The research-ers found that a combination of preop MMSE scores andan MMSE change score (between preop and postop) ac-counted for most of the variance in MMSE scores that weremeasured at a 10-month follow-up. This finding suggests



TABLE 3. Delirium Rating Scale (DRS) scores reported in different patient populationsAuthors Diagnosis (n) DRS scores (mean5SD) DRS Scores RangeTrzepacz et al. (1988) Delirious (20)

Demented (9)Schizophrenic (9)Other medical (9)

2354.84.652.13.351.6

0.6750.5

1230172701

Trzepacz et al. (1998) Delirious (18)Delirious-demented (43)

13.655.214.254.0

Rockwood et al. (1996) Delirious (36)Demented (16)Other psychiatric (18)Cognitively normal (27)

17.157.66.454.53.451.52.252.6

Rockwood et al. (1993) Delirious (48)Nondelirious controls (125)

17.054.0Not reported

1027

Goldstein and Fogel (1993) Mild postoperative cognitive impaired,nondemented elderly (82)

2.1752.73 016

Rosen et al. (1994) Delirious (70)Other organic mental disorders (291)Nonorganic psychiatric (430)

14.553.88.853.65.652.8

726

Tanaka et al. (1993) Delirium (7) 24

Wada and Yamaguchi (1993) Delirium (28):Duration .1 week (16)Duration #1 week (12)

16.553.318.452.7114.051.86

12-25

DiMartini et al. (1991) Post-operative liver transplant:On FK506 (14)On cyclosporine (10)

756552

Nakamura et al. (1994)a Delirium (76):Mianserin (46)

BaselineDay 5

Oxypertine (17)BaselineDay 1

Haloperidol (13)BaselineDay 5

21.251.08.050.9

20.150.812.351.3

22.051.39.551.4

Meagher et al. (1996) Delirium (46):Hyperactive (14)Hypoactive (11)Mixed (21)

20.25524.153.915.052.320.154.2

DiMartini et al. (1997) Postoperative liver transplant:On FK506 (17)On cyclosporine (14)

6.255.54.651.5

Only two cases in delirious range(19 and 22 points)

Breitbart et al. (1996) Delirium (30):BaselineDay 2End of treatmentBaseline haloperidol (11)Day 2 haloperidolEnd day haloperidolBaseline chlorpromazine (13)Day 2 chlorpromazineEnd day chlorpromazineBaseline lorazepam (6)Day 2 lorazepamEnd day lorazepam

20.153.513.356.112.856.420.553.512.555.911.656.120.653.912.156.511.956.718.352.617.354.217.055.0

1428326326

Trzepacz


TABLE 3. Delirium Rating Scale (DRS) scores reported in different patient populations (continued)Authors Diagnosis (n) DRS scores (mean5SD) DRS Scores RangeUchiyama et al. (1996)a Delirium (62):

Mianserin respondersMianserin nonresponders

21.953.222.253.3

Rudberg et al. (1997) Delirium (64):Single day (43)First day (20)

22.654.425.453.6

143118-32

Albronda et al. (1996) Delirium (43):AdmissionDischarge

14.56.6

Masand and Sipahimalani(1998)

Delirious (22):Baseline haloperidol (11)Post haloperidolBaseline olanzapine (11)Post olanzapine

20.155.011.157.117.954.410.354.8

Van der Mast (1994) Delirious (36):Postop day 3Maximum

Nondelirious (256):Postop day 3Maximum

13.857.219.055.7

4.151.74.451.9

729

111

aNotes that a modified DRS was used.

that the decline in cognitive function following surgery inthese nondemented elderly was not related to delirium, butrather to some other vulnerability for the later decline.

Outcome Studies

Albronda et al.25 studied 43 elderly patients (meanage: 78.5) hospitalized on a geriatric unit at ZiekenhuisRijnstate in Arnhem, Netherlands, who had a recent changein mental status. By using DSM-III-R criteria for diagnosis,28 had delirium, 23 dementia, 6 depression, and 21 mul-tiple problems. The mean DRS was 14.5 points within 3days of admission and 6.6 at discharge (P,0.001 for thisdifference in scores). Despite improvement in most pa-tients conditions they found that those admitted for recentmental status changes were at increased risk for nursinghome placement after discharge 53%, compared with13%, for geriatric admissions in general. The researchersdid not report any predictive data for the DRS, however.

Wada and Yamaguchi22 studied 28 elderly patientswho met DSM-III-R criteria for delirium (mean5SD age:67.759.1, range: 5083 years) who were referred to theNeuropsychiatric Unit of Kanazawa University Hospital.The DRS was administered the first day of admission. Thepatients were followed throughout their hospitalization anddivided into groups according to a clinical assessment ofduration of the delirium episode. In 16 patients, delirium

lasted more than 1 week. There was no difference in ageor gender for the patients whose delirium lasted #1 weekor .1 week, but DRS scores differentiated these groups(14.0 vs. 18.27, respectively; P,0.001). In addition, thegroup with shorter episodes had significantly lower scoresfor three DRS items: cognitive status (P,0.05), sleep-wake cycle disturbance (P,0.005), and mood lability(P,0.005). No comment was made about treatment fordelirium, though usual care was implied. These authorssuggested that the DRS may predict one dimension of de-lirium outcome (i.e., episode duration).

Rockwood et al.8 studied the outcome of educationalinterventions to recognition of delirium by housestaff atVictoria General Hospital in Dalhousie, Nova Scotia.Medical records were reviewed to compare 187 elderlycontrol patients consecutively admitted before the educa-tional intervention with 247 patients admitted thereafter.Housestaff were educated about delirium and in how to usethe CAM. Recognition of delirium or acute confusion, asdocumented in the record, was the outcome measure. Anindependent assessment was done by research nurses whoused the CAM and by research physicians who completedboth the CAM and the DRS. The CAM had a low sensi-tivity (0.68), compared with research physicians diagnosisof delirium using DSM-III-R. The educational interventionhad a significant impact on housestaff recognition of delir-ium. However, when compared with diagnosis by research



physicians, housestaff recognition had a sensitivity of 0.64and specificity of 0.93. DRS scores were not reported.

Rudberg et al.33 studied 432 elderly consecutively ad-mitted to medical and surgical wards of the University ofChicago Hospitals to assess characteristics of presentation,course, and duration of delirium. After using the CAM andattention tests to screen cases daily to identify possible de-lirium, research clinicians independently used DSM-III-Rcriteria for definitive diagnosis. Those identified as beingdelirious (about 15%) were rated daily by using the DRSto describe attributes of the delirium. The researchers foundthat 69% had delirium only for 1 day and that DRS scoreswere significantly higher for the first day (mean5SD:25.453.6) if the delirium lasted multiple days than if itlasted only 1 day (mean5SD: 22.654.4), suggesting thatmore severe delirium episodes last longer. The researchersfound no patterns of change among mean scores for indi-vidual DRS items over the multiple days, instead findingmuch interindividual variation for symptoms that was at-tributed to physiological differences from multiple medicaldiagnoses (mean5SD: 6.352.3 per patient) and multiplemedications (mean5SD: 6.952.6 per patient). Effects onDRS items related to whether and how delirium was treatedwere not discussed.

Treatment Studies

Nakamura et al.16 studied 53 delirious patients referredfor psychiatric consultation at Kurume University Hospital.Alcohol withdrawal patients were excluded. Theirmean5SD age was 69.5512.4 years. The patients wererated serially using a modified DRS (without items #1 and7) and treated with either mianserin (n446), oxypertine (aphenylpiperazine antipsychotic) (n417), or haloperidol(n413). Mean5SD DRS scores (see Table 3) decreasedin each drug group over time, though no statistical com-parisons were made between treatment groups nor weresurvival analyses performed. It was not mentioned whetherpatients were randomized to drug treatments or if the DRSwas rated blind to treatment status. Each evening through-out the study period, a single dose of drug was given. DRSscores correlated with plasma mianserin levels (r40.67,P,0.01) on Day 3 of treatment. The calculated differencebetween baseline DRS scores and Day 3 scores was in-versely correlated with mianserin plasma levels(r410.67, P,0.01), suggesting that mianserin was re-lated to delirium reduction.

Uchiyama et al.15 did an open trial of mianserin (1060 mg) treatment of delirium in 62 elderly patients hospi-

talized on a psychogeriatric unit of a general hospital,whose mean age was 80.7 years. DSM-IV categories fordelirium etiology were used. Twenty-five of these patients(40.3%) also had a preexisting dementia, and 8 were con-tinued on benzodiazepine hypnotics or morphine. Of the31 patients who had not responded to psychotropic treat-ment of their delirium episode, only 25 had received anantipsychotic (drug or dose was not reported). A 7-itemDRS was used for repeated measurements, with clinicalimprovement determined by improvement on at least fouritems and worsening on two or fewer items. Baseline5SDDRS scores did not predict response to mianserin(21.953.2 and 22.253.3). Rate of improvement on DRSitems included psychomotor behavior (85.5%), hallucina-tions (80.6%), sleep-wake cycle disturbance (82.3%), la-bility of mood (81.4%), delusions (79.6%), perceptual dis-turbances (67.7%), and cognitive status (48.4%). It washypothesized that mianserins H1 and 5-HT2 blocker ac-tivity might differentially affect certain delirium symp-toms.

Breitbart et al.26 did a double-blind, randomized com-parison of haloperidol, chlorpromazine, and lorazepam fordelirium in hospitalized AIDS patients at Memorial-SloanKettering Cancer Center in New York City. DSM-III-R cri-teria and a score of $13 on the DRS were used to diagnosedelirium in a prospectively assessed cohort of 244 patients,30 of whom (12%) became delirious. MMSE scores wereused to guide the rating of the DRS cognitive status item.The patients were rated hourly on the DRS during drugtreatment and, when scores exceeded 13 points, the nextdrug dosage was administered. The randomization to lor-azepam was stopped halfway through the study because allthose patients developed treatment-limiting adverse effects(e.g., increased confusion, sedation). They also showed noclinical improvement over the study period. DRS scores(see Table 3) significantly improved in each of the halo-peridol and chlorpromazine groups between baseline andDay 2, producing DRS scores below the delirium cutoffvalue within the first 24 hours of treatment. The mean doseof drugs given during the first 24 hours was 2.8 mg forhaloperidol, 50 mg for chlorpromazine, and 3.0 mg forlorazepam.

Masand et al.34 retrospectively completed the DRSbased on chart reviews in a nonrandomized naturalisticcomparison of delirious psychiatric patients treated witheither haloperidol (n411, mean5SD age: 63.5518.3)or olanzapine (n411, mean5SD age: 63.5523.2).Mean5SD pretreatment DRS scores were 20.155 forhaloperidol and 17.954.4 for olanzapine. Mean5SD

Trzepacz


posttreatment DRS scores were 11.157.1 for haloperidoland 10.354.8 for olanzapine. Clinical improvement wassimilar in each group, though there were methodologicalissues, including nonrandomization, simultaneous use ofother neuroleptics in the olanzapine group, and deliriumbeing comorbid with other Axis I diagnoses that sharesome of its symptoms.

Meagher et al.23 examined the pattern and frequencyof use of environmental interventions and psychotropicdrug use in delirium management. Consecutive referrals toa consultation-liaison (C-L) psychiatry service in a largegeneral hospital in Dublin were prospectively assessed fordelirium by using ICD-10 criteria for diagnosis and theDRS for symptom severity. Mean5SD age of the samplewas 60.1519.5 years, and mean5SD DRS was20.1754.98. The patients received a mean5SD of4.0451.87 nursing interventions. When separated intohigh and low intervention groups (using cutoff of four in-terventions), the high group was found to have greater de-lirium severity (P,0.01), though the DRS score was notreported. The DRS was also divided into two core sub-scales: cognitive, which included cognitive status, de-lusions, and hallucinations, and behavioral management,which included psychomotor behavior, sleep-wake cycledisturbance, and mood lability. Nursing intervention scoreswere significantly associated (P,0.01) with the DRS be-havioral management core scores but not with cognitivecore scores.

REVISION OF THE DRS

The DRS is very useful clinically, and its routine use canenhance the detection of delirium symptoms as well as as-sist trainees to appreciate the breadth of the delirium syn-drome. Use of the DRS for research purposes has high-lighted some of its shortcomings. To be more useful as aresearch tool, the DRS needs to be revised by separatingitems more relevant for diagnosis from items more relatedto symptom severity, which will allow its use during re-

peated serial ratings in intervention studies. To be used toadvance phenomenologic research of delirium, the DRSneeds to be more comprehensive in its ability to detectabnormalities of cognitive, behavioral, thinking, and lan-guage functions that have been described in the clinicalliterature.

Thus, the revised DRS will include separate items foreach cognitive function (disorientation, attention, memory,etc.), irrespective of whether formal, standardized cogni-tive tests are administered as an adjunct. The revised DRSwill separate psychomotor items into one for hyperactiveand one for hypoactive states. It will add items that eachrate the severity of thought process and language abnor-malities, to address what constitutes the problems that aretraditionally represented by the terms confusion orclouding of consciousness.

The revised DRS is now being validated against theoriginal DRS and will become available for translation andinternational crossvalidation during 1999.

CONCLUSIONS

C-L research requires standardized rating instruments tomeasure symptoms and improve methodological quality.35Delirium is still an understudied disorder and is of majorclinical importance to C-L psychiatrists. The DRS is themost widely used and best studied of instruments designedspecifically for use in delirium. It has been shown to haveexcellent scale characteristics and reliability, to serve as asymptom severity scale, and to be responsive to change indelirium status during treatment. Recommended cutoffscore for the DRS is about 12 points, though choosing acutoff score also depends on the study design, in whichsensitivity or specificity may be affected by context orcomparison groups.

Though the revised DRS will be better suited for phe-nomenological and treatment studies of delirium, the origi-nal DRS will still be useful and valid for clinical and re-search purposes in C-L psychiatry.

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