a family-focused randomized controlled trial to prevent adolescent alcohol and tobacco use: the...

A Family-Focused Randomized Controlled Trial to Prevent Adolescent Alcohol and Tobacco Use:The Moderating

Roles of Positive Parenting and Adolescent Gender

D e b o r a h J.Jones, University of North Carolina at Chapel Hill Ardis L. Olson, Dartmouth Medical School

Rex Forehand, University of Vermont Cecelia A. Gaffney, Michael S. Zens, Dartmouth Medical School

J.j. Bau, University of Georgia

Four years of longitudinal data from 2,153 families with a 5th- or 6th-grade preadolescent participating in a family- focused pediatric primary-care-based prevention program were used to examine whether prevention effects were moderated by positive parenting and/or adolescent gender. Alcohol and tobacco use, internalizing problems, and externalizing problems were examined. Although findings revealed no main effect of the prevention program, positive parenting and adolescent gender were moderators of internalizing problems and adolescent gender was a moderator of externalizing problems. Clinical implications and future direc- tions for research are discussed.

A L T H O U G H I N C R E A S I N G A T T E N T I O N has been devoted to the prevention of adolescent substance use, alcohol and tobacco use among adolescents re- mains a primary public health concern. Approxi- mately half (45.6%) of high school students have consumed alcohol by eighth grade and 20.3 % have been drunk in the same period (Johnston, O'Malley, Bachman, & Schulenberg, 2004). Among eighth graders, 30% report that they have tried cigarettes in the past 30 days (Johnston et al., 2004). Cauca- sian adolescents are at highest risk for alcohol, cigarette, and smokeless tobacco use relative to their African American and Hispanic peers; therefore, prevention efforts that target preadolescent Cauca- sian youth are of particular importance (Johnston et al., 2004).

This research was supported by the National Institute on Alco- hol Abuse and Alcoholism (NIAAA).

Address correspondence to Deborah J. Jones, Department of Psychology, Davie Hall, CB # 3270, University of North Carolina, Chapel Hill, NC 27599-3270; e-mail: [email protected]. BEHAWOR THERAPY 36, 347--355, 2005 005-7894105/0348-035551.00/0 Copyright 2005 by Association for Advancement of Behavior Therapy All rights for reproduction in any form reserved.

A l c o h o l and T o b a c c o U s e Prevent ion The majority of alcohol and tobacco prevention programs have been conducted in the schools (e.g., Botvin, Baker, Dusenbury, Botvin, & Diaz, 1995; Peterson, Kealey, Mann, Marek, & Sarason, 2000). The contribution of such programs is questionable, however, given the relatively high rates of use post- program (D'Amico & Fromme, 2002), the null findings following some school-based programs (Peter- son et al., 2000), and the inaccessibility of the family, which plays a significant role in adolescent substance use (e.g., Biglan et al., 1996; Peterson et al., 2000). Accordingly, some have suggested moving adolescent alcohol and tobacco use prevention work into primary care settings, where adolescents are a generally captive audience and parents are present (Botvin et al., 1995; Johnson & Millstein, 2003).

The Dartmouth Prevention Project (DPP; Stevens et al., 2002) was a National Institute on Alcohol Abuse and Alcoholism (NIAAA) funded randomized control trial (1992-1996) that utilized pediatricians in primary care settings to deliver substance use prevention messages. Initial findings from the DPP revealed that the prevention program was not more effective in preventing adolescents from ever trying alcohol or tobacco than the control condition (Stevens et al., 2002). The purpose of the current project was to examine potential moderators of the substance use prevention program, as well as to examine two additional outcomes: adolescent internalizing and externalizing problems.

A L C O H O L A N D T O B A C C O U S E

P R E V E N T I O N A N D A D O L E S C E N T

P S Y C H O S O C I A L A D J U S T M E N T

Substance use prevention programs target youth at relatively young ages, with the intention of preventing substance use initiation for most preadolescents or preventing continued use and misuse among others. As a function of the design of such studies,

3 4 8 J O N E S E T A L .

most youth enrolled in a prevention program will not have used substances at baseline and only a small percentage of youth will have used after the prevention program, yielding relatively little variability in substance use outcomes. Accordingly, other outcomes should be examined as well, particularly psychosocial correlates of adolescent substance use.

Psychosocial adjustment difficulties generally co- occur with adolescent alcohol and tobacco use and are typically considered risk factors (see Myers, Brown, Tate, Abrantes, & Tomlinson, 2001, for a review). Among community samples, over half (60%) of adolescents meeting substance use, abuse, or dependence criteria also had a comorbid psychiatric condition, including internalizing (e.g., depression) and externalizing (e.g., conduct disorder) spectrum disorders (Armstrong & Costello, 2002). The ro- bust link between adolescent substance use and internalizing and externalizing problems suggests that prevention of these problems among preadolescents may, in turn, prevent alcohol and tobacco use as well (see Glantz, 2002, for a review). Thus, the first purpose of the current study is to extend the findings presented by Stevens et al. (2002) by examining whether the prevention program was associated with lower levels of internalizing and externalizing problems among adolescents than the control group.

M O D E R A T O R S O F A L C O H O L A N D

T O B A C C O U S E P R E V E N T I O N

The inclusion of families in DPP also presents a unique opportunity to examine how family characteristics may moderate the effect of the prevention program, providing information about the types of families for whom substance use prevention programs may be more or less effective and under what conditions (Kraemer, Wilson, Fairburn, & Agras, 2002). In the only other study to date which examined a family-based moderator of an adolescent substance use prevention program, Guyll and colleagues (2004) did not find that parental adjustment (i.e., a combination of parental depression, anxiety, and hostility) moderated the effect of the family-focused prevention program on adolescent substance use. The authors noted, however, that other family-based moderators of adolescent substance use prevention programs should be examined. The second purpose of this study is to examine another family-based moderator of adolescent substance use prevention: positive parenting.

As adolescents age, concern for parental disap- proval becomes an increasingly important factor in their decision not to use substances (Johnston et al., 2004). Additionally, certain parenting behaviors, notably parenting behaviors characterized by a balance of warmth and support, control and disci-

pline, and clear expectations, have consistently been protective of adolescent health and well-being. These parenting behaviors are based on both social learning theory and coercion theory (see McMahon & Forehand, 2003, for a review). Furthermore, this positive parenting style has been associated with a wide range of adolescent outcomes, including less risk for internalizing and externalizing difficulties generally (see Basic Behavioral Science Task Force, 1996, for a review), as well as lower rates of adolescent substance use in particular (e.g., Ary et al., 1999). Accordingly, the effect of family-based prevention programs targeting adolescent alcohol and tobacco use may depend not only on the inclusion of parents, but also on their parenting behavior during the course of the study. Specifically, we were in- terested in whether positive parenting moderated the efficacy of our prevention program. Were preadolescents in the prevention group whose parents engaged in higher levels of positive parenting less likely to engage in alcohol and tobacco use and less likely to evidence internalizing and externalizing problems than preadolescents in the prevention group whose parents engaged in lower levels of positive parenting or preadolescents in the control group?

Examining characteristics of the child may also inform us for whom substance use prevention programs are most effective (Kraemer et al., 2002). Research from several areas (e.g., parenting programs, nonclinical samples, correlational studies) suggests that the gender of the child may be a potential moderator. In most (see Borawski, Ievers- Landis, Lovegreen, & Trapl, 2003; McMahon & Wells, 1998; Rothbaum & Weisz, 1994), but not all (Weisz, Weiss, Han, Granger, & Morton, 1995), instances boys are more responsive to parenting and parenting interventions than girls. Boys also are more likely than girls to engage in at least one risky behavior (Biehl et al., 2002), particularly alcohol use (Ozer et al., 2003). The third purpose of the current study is to examine adolescent gender as a moderator of our prevention program.

H Y P O T H E S E S

Based on the findings of Stevens et al. (2002), we did not hypothesize that the prevention program would have a main effect on adolescent alcohol and tobacco use. However, we predicted that there would be a main effect of the prevention program on adolescent internalizing and externalizing problems, such that adolescents randomized to the alcohol and tobacco use prevention program would have lower levels of internalizing and externalizing problems than adolescents in the control group. Additionally, we hypothesized that the prevention program would be most effective for adolescents

P R E V E N T I N G A D O L E S C E N T A L C O H O L A N D T O B A C C O U S E 349

whose parents evidenced higher levels of positive parenting. Although most studies of positive parenting focus on mothers, research in recent years suggests that parenting by fathers is also important (see Phares, 1996, for a review). Thus, we examined the role of both mothers' and fathers' positive parenting and hypothesized that both will serve as moderators. Finally, we hypothesized that gender would moderate prevention success. As the majority of research suggests that effects may be more pronounced with boys than with girls, we hypothesized that boys would be more responsive to the prevention program than girls.

Method P A R T I C I P A N T S

Of the 4,096 families approached by participating primary care physicians during the 21-month recruit- ment period of the DPP, 3,525 (86%) parent-child dyads agreed to participate and 3,496 (85%) met the grade eligibility requirements (i.e., child in fifth or sixth grade). Of the eligible families, 3,094 (77%) completed the baseline assessment, 2,741 completed the 12-month assessment, 2,481 completed the 24-month assessment, and 2,172 completed the 36-month assessment. Of those families complet- ing the study, 2,153 (n = 1,235 in substance use group, n = 918 in control group) had complete data at all assessments and were included in this report. Reasons for attrition included losing contact with the families who moved and parents with- drawing from the study.

In order to be enrolled in the study, preadolescents had to be in the fifth or sixth grade and accompanied to the well-child visit by a parent or legal guardian. Only one preadolescent and parent in a family partic- ipated. In 91% of the families, the mother was the participating parent. The demographic characteristics of the 2,153 participating parents and preadolescents at the time of enrollment are reported in Table i by group (prevention and control). The groups differed only on gender of the preadolescent.

M E A S U R E S

Demographics. Preadolescents and parents reported demographic information, including gender (both child and parent), age (both child and parent), highest level of parent's education (parent), ethnicity (parent), and family income (parent). De- mographic data from the baseline assessment were utilized for the current study.

Prevention program. Each of the 12 participating clinics was randomly assigned within pairs to either the substance use (prevention) group or bicycle helmet, car seatbelt, and gun safety (control) group, with six clinics in each condition.

TABLE I Demographic Characteristics o f Substance Use Prevention Program and Control Groups at Assessment I (N = 2,153)

M (SD) or % (n)

Variable Prevention Control t or X 2

Adolescent Age (yrs.) 10.96 (,87) 10.95 (.81) - .18 % Female 41% (506) 59% (54 I) 38.05*

Education a Mother 14.55 (2.47) 14.48 (2.45) - . I 0 Father 14.92 (2.86) 14.81 (3.05) - .79

Family Annual Income b 14.07 (3.26) 13,88 (3.47) - .72 % Married 88% (I,087) 88% (808) .01 % Caucasian c 97% ( I, 198) 97% (890) .06

a Mean years of education. b 14 = $40,000--$44,999; I 5 = $45,00(~$49,000. c Non-Hispanic, *p < .01.

Positive parenting. Assessments 2 (12 month) and 3 (24 month) measures were utilized to assess positive parenting of mothers and fathers during the course of the prevention program. The three dimensions of our positive parenting construct were assessed using items from two subscales from Barnes and Farrell (1992), who reported adequate reliabil- ity and validity for both subscales. Subscales were shortened for the purposes of this investigation due to space and time constraints. All items were completed by the adolescent.

Parental warmth and support was measured with five items from Barnes and Farrell's 8-item Support subscate. Each item was completed on a 1 (always) to 5 (never) scale, with lower scores indicating more warmth. A sample item is "When you do something well, how often does your mother/father praise you?" The alpha coefficients for these five items at Assess- ment 2 were .75 and .80 and at Assessment 3 were .78 and .80 for mothers and fathers, respectively.

Parental discipline was measured with four items from Barnes and Farrell's (1992) Control subscale. Each item was completed on a I (always) to 5 (never) scale, with lower scores indicating more positive discipline strategies. A sample item is "How often does your mother/father take away your privileges (TV, movies, dates) when you disobey or do something of which your parent does not approve?" The alpha coefficients at Assessment 2 were .67 and .76 and at Assessment 3 were .68 and .78 for mothers and fathers, respectively.

Clear expectations for adolescent behavior was assessed by a single item from the Barnes and Far- rell (1992) Control subscale: "In general, do you

3 5 0 J O N E S ET AL.

know what your [mother/father] expects of you?" This item was completed on a 1 (always) to 5 (never) point scale with lower scores indicating clearer expectations.

In order to form a positive parenting construct, each of the three dimensions (warmth, appropriate discipline, clear expectations) was standardized at Assessments 2 and 3, and then averaged across the two assessments. The three dimensions were then summed, and provided an assessment of positive parenting during the intervention. Correlations between the dimensions of positive parenting across Assessments 2 and 3 averaged .51 (range: .42 - .67) for mothers and .53 (range: .47 - .69) for fathers (p < .01 in all cases), suggesting stability across assessments.

Adolescent alcohol and tobacco use composite index. Assessments 1 and 4 measures of adolescent alcohol and tobacco use were utilized. Adoles- cent-reported alcohol, cigarette, and smokeless tobacco use was assessed using eight questions. Four questions assessed alcohol use: "Ever had a drink?" "How many times have you had a drink in the past 30 days? .... How often have you been drunk in the past 30 days?" and "Problems with drinking." Two items assessed cigarette use: "Have you ever smoked cigarettes?" and "How many times have you smoked a cigarette in the past 30 days?" Two items assessed smokeless tobacco use: "Have you ever used smokeless tobacco?" and "Have you used smokeless tobacco in the past 30 days?" All eight questions were dichotomized, with answers of "no" coded as 0 and answers of "yes" coded as 1. Following the recent work of Guyll et al. (2004), an index was created by summing the dichotomized responses from all eight items, yielding a measure that could range from 0 to 8. Because this index exhibited a skewed distribution at each assessment and transformations of the data did not normalize the distribution of scores, we dichotomized the index such that preadolescents who responded "no" to all eight items received scores of 0 and those who responded "yes" to one or more items received a score of I (e.g., Guyll et al., 2004).

Adolescent psychosocial adjustment. Adolescent internalizing and externalizing symptoms at As- sessments 1 and 4 were assessed by parent report on the Pediatric Symptom Checklist-17 (PSC-17; Gardner et al., 1999), a brief version of the Pediat- ric Symptom Checklist (e.g., Murphy et al., 1992). The PSC-17 is a 17-item questionnaire with three subscales designed to tap internalizing and externalizing symptoms, which were the focus of the current study, as well as attention difficulties. Par- ents rated internalizing and externalizing symptoms on a 3-point Likert-type scale as occurring often, sometimes, or never.

The subscales of the PSC-17 have been shown to be both reliable and valid (Gardner et al., 1999). Sample items from the Internalizing Symptoms subscale include the adolescent "feels sad, unhappy" and "feels hopeless." The five items of the PSC that assess adolescent internalizing symptoms yielded an alpha of .76 and .77 at Assessments 1 and 4, respectively, for the current sample. Sample items from the Externalizing Symptoms subscale include "fights" and "does not listen to rules." The five items that assess externalizing symptoms yielded an alpha of .80 and .70 at Assessments I and 4, respectively, for the current sample. Higher scores on each scale indicated higher levels of these symptoms.

Family response to prevention program. A subsample of 57% of the adolescents and parents completed a questionnaire at Assessment 4 (36 months) indicating whether they continued communication about risk behaviors, had a family policy in place, and perceived benefits from participating in the project. This subsample was randomly selected from those families still participating at Assessment 4.

P R O C E D U R E

Training. All pediatricians and nurse practitioners in every practice were trained by project staff during a 3-hour session on-site. The training session focused on how clinicians could shift the focus of well-child visits from screening to family communication about risk behavior (substance use or safety). (See Stevens et al., 2002, for further details.)

Ongoing practice supports. The pediatric practices received a "message of the month," feedback from chart audits, calls, and routine visits from research coordinators for problem identification and solving. Staff/clinician newsletters were sent quarterly to all participating practices. The newsletter content varied by prevention group and over time.

Prevention program. All participating preadolescents and parents were recruited during a well-child visit and signed informed assent and consent forms, respectively. The role of physicians in this study was to educate families about risks associated with substance use (prevention program) or lack of safety (control group), encourage family communication about the risks, and to encourage families to establish policies and engage in activities that would prevent risky behavior. At the initial visit, participating families agreed to discuss the target risk behaviors and to develop a family policy about those behaviors. Parent, child, and clinician signed a "family contract" which stated that the family would discuss the prevention program at home and develop a family policy regarding the target behavior (e.g., policy regarding risk behavior, consequences for vi- olating policy). Depending on the practice's ran-


domization status, alcohol, smoking, and smokeless tobacco use (substance use prevention group) or bicycle helmet, car seatbelt, and gun safety (safety control group) were the risk behaviors iden- tified and targeted (see Stevens et al., 2002, for further details).

As a check on practiceqevel compliance and as is detailed by Stevens et al. (2002), over 99% of participants' charts contained the family contract and a flow sheet documenting subsequent messages. Quar- terly audits revealed that 95% of the participating adolescents were seen for at least one subsequent office visit during the course of the study. The pro- portion of office visits with a documented prevention message averaged 47% in the control (safety) condition sites and 51% in prevention program (substance use) sites. As noted by Stevens et al. (2002), this rate is likely an underestimate of the actual de- livery of prevention messages as only those messages which clinicians documented in a research flow sheet were counted.

The prevention program was further supported by three sets of materials mailed to families: bro- chures focusing on effective communication; annual reminders (e.g., card game, magnets and pens with prevention program messages); and separate quarterly newsletters for parents and adolescents with role-appropriate information and messages. The communication skills emphasized in each newsletter were identical in the prevention and control conditions. Only the health risk behaviors targeted differed for the two conditions. Newsletters were mailed quarterly during each of the 3 years of the prevention program.

Assessment. Questionnaire packets were mailed to each participating parent and child dyad. Parents and children were instructed to complete their re- spective questionnaire packets independently and to return them independently using the stamped and addressed envelope that each of them was provided. The same procedures were followed at Assess- ment 1 (pre-prevention program), Assessment 2 (12 months after baseline), Assessment 3 (24 months after baseline), and Assessment 4 (36 months after baseline) for the substance use prevention and control groups.

Once both the parent and child questionnaire packets for a participating family were returned, the child received $5. If questionnaire packets were not returned in 4 weeks, the child and parent received a reminder card. If the packets were not returned in 6 weeks, the family received a reminder telephone call. If families had moved, efforts (e.g., sending a card, attempting to locate families through neigh- bors, families, and telephone directory assistance) were implemented in an attempt to locate them.

Results F A M I L Y R E S P O N S E T O T H E

P R E V E N T I O N P R O G R A M

A subset of the families retained at Assessment 4 (57%) were asked whether or not they continued communication regarding the target behaviors, whether a family policy was in place, and the perceived benefits of the prevention program. Among that subset of families, 97% of those in the substance use prevention program and 77% of those in the control group endorsed ongoing communication about the prevention target behaviors and approximately half of the families in each of the groups (50% in the prevention group and 46% in the control group) indicated having a family policy in place. Eighty-nine percent of those in the substance use prevention group and 85% in the control group indicated that the prevention program facilitated family communication about the target behavior.

P R E L I M I N A R Y A N A L Y S E S

The percentage (dichotomized variables) or mean (externalizing and internalizing problems) for each dependent variable is presented for boys and girls in the prevention and control groups at Assessment 1 (pre-prevention program) and 4 (36 months) in Table 2.

The participants who were retained at Assessment 4 and those not retained were compared on all demographic variables (Table 1) and on all dependent variables (Table 2) at baseline by t tests (continuous variables) or chi-square statistics (dichotomous variables). The results indicated that, relative to those retained, children who were not retained were older and more likely to be male and mothers and fathers had lower educational levels, had lower monthly family incomes, and were less likely to be married (p < .01 in all cases). The original sample of 1,780 substance use prevention program families and 1,331 control families did not differ on child mean age, parent's education, family income, and marital status of parents (p > .40 in all cases); however, as with the retained sample (see Table 1), they did differ on gender of adolescent (41% and 59% female in substance use prevention program and control groups, respectively, p < .01).

Finally, prevention group was nested within clinic (i.e., six clinics were assigned to the prevention condition and six were assigned to the control condition). In order to examine whether clinic effects emerged, hierarchical linear modeling analyses were performed that included clinic as a random factor. For all dependent variables, the clinic factor was not statistically significant and, thus, was not considered further.

3 5 2 J O N E S ET A L .

TABLE 2 Percent or Mean for Each Dependent Variable for Boys and Girls in the Substance Use Prevention and Control Groups at Assessments I and 4

Substance Use Prevention Control

Boys Girls Boys Girls

Variable % (n) M (SD) % (n) M (SD) % (n) M (SD) % (n) M (SD)

ATUI (% yes) Assessment I Assessment 4

Externalizing Problems Assessment I Assessment 4

Internalizing Problems Assessment I Assessment 4

14 (123) 10 (85) 13 (96) 9 (56) 28 (I 67) 33 (217) 28 (I 36) 29 (I 32)

2.85 (I .90) 2.10 (I .68) 2.73 (I .84) 2.28 (I .76) 2.55 (1.92) 2.07 (I .80) 2.74 (I .94) 2.09 (I .85)

2.14 (I .88) 2.01 (I .76) 2.05 (I .77) 2. I I (I .79) 1.78 (I .83) 2.04 (I .77) 1.90 (I .90) 2.07 (I .90)

Note. ATUI = Alcohol andTobacco Use Index,

P R I M A R Y ANALYSES

Prior to the regression analyses, the two continuous predictor variables, maternal positive parenting and paternal positive parenting, were centered to im- prove the interpretation of possible interactions and reduce multicollinearity (Aiken & West, 1991). The dichotomous dependent variable, the adolescent alcohol and tobacco use index, was examined by logistic regression and continuous dependent variables were examined by linear regression. In Block 1, the variable that differed for the substance use prevention and control groups (adolescent gender) was entered. For the internalizing and externalizing problems outcome variable, the baseline score on the dependent variable also was entered in Block 1, providing the opportunity to examine change. For the alcohol and tobacco use index outcome variable, those preadolescents who endorsed use at baseline were excluded from the analyses so that onset of use could be examined. In Block 2, prevention program (control group = 0 and substance use prevention group = 1) was entered. In Block 3, maternal positive parenting (averaged over Assess- ments 2 and 3) and paternal positive parenting (averaged over Assessments 2 and 3) were entered. The moderating variables were positive parenting and adolescent gender. Our intent was to enter these variables after the prevention program variable, so that we could ascertain the effects of prevention program initially. However, as adolescent gender differed between the control and treatment groups, we entered this variable in the first block to control for the differences. In Block 4, six 2-way interactions in- volving treatment, adolescent gender, maternal positive parenting, and paternal positive parenting were entered. In Block 5, the four 3-way interactions in- volving the same variables were entered.

The main effect and interaction terms of interest

focused on the prevention program variable and its interaction with adolescent gender, maternal positive parenting, and paternal positive parenting. As expected, there was not a main effect of the prevention program on the alcohol and tobacco use index, b = - . 19, ns. Contrary to our hypotheses, maternal positive parenting, b = .11, ns, paternal positive parenting, b = .13, ns, gender of the adolescent, b = .04, ns, and the interaction of these variables, b = .03, ns, in all cases, did not moderate the effect of the prevention program on the alcohol and tobacco use index.

There was also no main effect of the prevention program on either adolescent internalizing, b = - .07 , ns, or externalizing, b = - .09 , ns, problems. However, for externalizing problems, a significant Prevention Program × Adolescent Gender interaction was obtained, b = .39, p < .01. For internalizing problems, a 3-way interaction of Prevention Program × Adolescent Gender × Paternal Positive Parenting moderated prevention program effects, b = - .18 , p < .05.

In order to explicate the significant 2- and 3-way interactions, the calculation tool for probing significant interactions developed by Preacher, Curran, and Bauer (2004) was utilized. As demonstrated in the upper graph of Figure 1, boys in the prevention program had lower levels of externalizing problems than boys in the control group at the 36-month assessment. As demonstrated in the bottom graph of Figure 1, boys in the prevention program whose fathers engaged in higher levels of positive parenting had significantly lower levels of internalizing problems than boys in the control group whose fathers engaged in higher levels of positive parenting. Furthermore, boys in the prevention program whose fathers engaged in higher levels of positive parenting had lower levels of internalizing prob-


0 .20

0 .15

E 0 .10

- 0 . 05 m

-0 .10

- 0 . 15

- 0 . 20

Girls Boys

Control Group P~enfion Group

0 .20

0 ,10

o.oo o.

= -O.lO

E - o . 2o

- 0 . 30

- 0 . 40

- 0 . 50

n.s. Low PP, Girls

High PP, Girls

Low PP, Boys

High PP, Boys

Control Group Prevention Group

FIGURE I Top: Two-way interaction of Gender of Adoles- cent x Prevention Program predicting externalizing problems at Assessment 4. Bottom: Three-way interaction of Gender of Ado- lescent x Prevention Program X Paternal Positive Parenting predicting internalizing problems at Assessment 4.

lems than the remaining three groups in the prevention program (see Figure 1).

Discussion The impact of a family-focused alcohol and tobacco use prevention program, implemented in pediatric primary care settings, was examined. As expected, based on the earlier findings of Stevens et al. (2002), there was no main effect of the prevention program on adolescent alcohol and tobacco use, internalizing problems, or externalizing problems. Adolescents in the prevention group did not evidence significantly lower levels of alcohol and tobacco use, internalizing, or externalizing problems than adolescents in the control group at the 36- month assessment. Furthermore, neither positive parenting nor gender of the adolescent moderated the effect of the prevention program on adolescent alcohol and tobacco use. In contrast, moderation did occur for adolescent internalizing and externalizing problems. The effect of the prevention program on these problem behaviors depended on the gender of the adolescent and, in the case of internalizing problems, also on paternal positive parenting. Specif- ically, boys in the prevention program demonstrated fewer externalizing problems at the 36-month assessment than boys in the control condition. Further- more, boys in the prevention program demonstrated

fewer internalizing problems, but only when positive parenting by fathers occurred at higher levels.

One possible explanation for the lack of main or moderated effects with adolescent alcohol and tobacco use is the relatively low levels of use in this sample. The rates of both alcohol and tobacco use in the DPP sample were significantly lower than the national averages for adolescent use reported else- where (Johnston et al., 2004). Caucasian adolescents are at greater risk for alcohol and tobacco use than minority adolescents; however, higher socio- economic status is associated with lower levels of use (Johnston et al., 2004). The majority of families in the DPP sample were middle or high income and all families were recruited from pediatric primary care clinics, suggesting that families had health insurance and were of upper-middle-class status. Targeting families from a relatively high socioeco- nomic status and children at a relatively young age decreased the likelihood that these adolescents would use alcohol or tobacco during the course of the study and, thereby, decreased the opportunity for a prevention or moderated prevention effect. Fu- ture research in this area should attempt to target medical settings that serve a wider range of families.

Although there were no main or interactive effects for adolescent substance use, the prevention program may indirectly influence adolescent alcohol and tobacco use via its effect on adolescent internalizing and externalizing problem behaviors. Previous research has indicated a strong association between each of these two types of problem behaviors and substance use (e.g., Armstrong & Costello, 2002), suggesting that successful prevention efforts may include reductions in these behaviors as well. Our findings indicate that both internalizing and externalizing problem behaviors were reduced through the prevention program; however~ this occurred only for boys and, in the case of internalizing problems, only when paternal positive parenting occurred at higher levels. Boys in the prevention program evidenced significantly lower levels of externalizing problems at the 36-month assessment relative to boys in the control condition. Of note, the explication of the interaction suggested the opposite, albeit nonsignificant, pattern of findings for girls (i.e., girls in the prevention program evidenced higher levels of externalizing problems relative to girls in the control group). The opposite pattern of findings for boys and girls accounts, at least in part, for the failure to find a main effect of the prevention program on externalizing problems. Accordingly, future research in this area should further consider the role of adolescent gender in alcohol and tobacco use prevention efforts.

Our findings with internalizing and externalizing problems are consistent with the general literature on

3 5 4 J O N E S ET A L .

parenting, which suggests that such programs may be more effective with boys than girls (see McMahon & Wells, 1998, for a review). Additionally, as we have noted, boys' behavior problems appear to be more responsive to parenting strategies than those of girls (Rothbaum & Weisz, 1994). However, it should also be noted that families with boys are more likely to drop out of prevention and intervention programs generally (see McMahon & Wells, 1998, for a review), and our findings are not an ex- ception: the nonretained sample included a higher percentage of families with boys than the retained sample. Thus, our findings indicate that, when gender effects emerge, a substance use prevention program is more effective with boys than girls; however, families with boys are less likely to complete the program. Future research efforts should address ways to not only retain boys in family-focused substance use prevention programs in primary care settings, but also attempt to increase the effective- ness of such programs for girls.

As noted, our findings suggest that, in addition to gender of the adolescent, paternal positive parenting is an important variable when internalizing problems is the outcome of interest. Boys in the prevention program whose fathers engaged in higher levels of positive parenting evidenced lower levels of internalizing problems at the 36-month assessment relative to all other groups. This finding has two important implications. First, at least for some outcomes, inclusion of parents in prevention programs may not be sufficient: A focus on positive parenting may be necessary to achieve a successful outcome. Second, as Phares (1996) has emphasized, fathers should not be ignored when implementing family- focused programs. Similar to the findings for externalizing problems, the differential pattern of findings across groups may also have accounted for the failure to detect a significant main effect of the prevention program on internalizing problems. That is, there was a nonsignificant trend in the data suggesting that some adolescents in the prevention group (i.e., girls whose fathers engaged in higher levels of positive parenting and boys in the prevention program whose fathers engaged in lower levels of positive parenting) evidenced higher levels of internalizing problems than their counterparts in the control group. Again, these trends should be considered in future adolescent alcohol and tobacco use prevention efforts with the aim of further disentangling for whom and under what conditions prevention efforts are most effective.

As with all research, the findings of this study must be interpreted in light of its limitations. First, other than prevention group assignment, all variables of interest were measured by self-report alone. Future work should attempt to replicate and extend

our findings by including other types of measure- ment, including observational measures of positive parenting. Second, preliminary analyses revealed that the retained and nonretained families differed on demographic variables and two outcome variables. Although consistent with analyses of drop- out in other parenting programs (for a review see McMahon & Wells, 1998), such differences limit the conclusions that can be drawn about our family- focused prevention program administered in the context of primary care. Third, clinics were randomly assigned within pair to prevention or control group. Hierarchical linear modeling, which included clinic as a random factor, did not reveal that this factor exerted a significant effect; nevertheless, future research should consider implementing both prevention and control conditions in each clinic and randomly assigning participants to one of these two conditions. Fourth, our fidelity checks suggest that almost 100% of our participating clinicians and families signed a family contract which stated that the family would discuss the prevention message at home and establish a family policy regarding the target behavior, but only approximately half of the participating families reported actually having such a policy in place at the 36-month assessment. Future research should examine how to facilitate the process of establishing family policies. Fifth, we do not have data indicating whether the mother, father, or both parents delivered the prevention messages in the home. Thus, future work should attempt to gather more information regarding not only whether the prevention messages are being delivered, but by whom. Sixth, our findings suggest that the prevention program was more effective for internalizing and externalizing problems of boys than girls; however, this finding may be a function, at least in part, of the differential attrition rate for boys and girls. Finally, the findings of this study should not be generalized beyond Caucasian, predominantly intact, middle-income families.

Strengths of the current study also merit attention. First, only one other study has examined a family-focused moderator, parental adjustment, of an adolescent substance use prevention program (Guyll et al., 2004). We extended this literature by examining the moderating role of positive parenting. Second, this study was prospective, examining adolescent alcohol and tobacco use over the course of 3 years (from fifth/sixth grade to eighth/ninth grade), providing the opportunity to examine initiation of substance use during this period. Third, our study examined positive parenting of both mothers and fathers. Finally, participating parents and children received a set of 24 newsletters conveying prevention messages, and the vast majority of families surveyed endorsed ongoing communication about


the target behavior. These findings indicate that the programs were implemented at a sufficient level for evaluation to occur.

In conclusion, the findings from this study suggest that prevention programs may effect change in psychosocial correlates of adolescent alcohol and tobacco use, namely, internalizing and externalizing problems. Furthermore, both adolescent gender and positive parenting should be considered when implementing and evaluating substance use prevention programs.

References

Aiken, L. S., & West, S. G. (1991). Multiple regression: Testing and interpreting interactions (pp. 9-27). Newbury Park, CA: Sage.

Armstrong, T. D., & Costello, E.J. (2002). Community studies on adolescent substance use, abuse, or dependence and psychiatric comorbidity: A literature review. Journal of Con- sulting and Clinical Psychology, 70, 1224-1239.

Ary, D. V., Duncan, T. E., Biglan, A., Metzler, C. W., Noell, J. W., & Smolkowski, K. (1999). Development of adolescent problem behavior. Journal of Abnormal Child Psychology, 27, 141-150.

Barnes, G. M., & Farrell, M. P. (1992). Parental support and control as predictors of adolescent drinking, delinquency and related problem behaviors. Journal of Marriage and the Family, 54, 763-776.

Basic Behavioral Science Task Force. (1996). Basic behavioral research for mental health. American Psychologist, 51, 622-630.

Biehl, M. C., Park, M. J., Brindis, C. D., Pantell, R. H., & Irwin, C. E. (2002). The health of America's middle childhood population. San Francisco: University of California, San Fransico, Public Policy Analysis and Education Center for Middle Childhood and Adolescent Health.

Biglan, A., Ary, D., Yudelson, H., Duncan, T. E., Hood, D., James, L., Koehn, V., Wright, Z., Black, C., Levings, D., Smith, S., & Gaiser, E. (1996). Experimental evaluation of a modular approach to mobilizing antitobacco influences of peers and parents. American Journal of Community Psy- chology, 24, 311-339.

Borawski, E. A., Ievers-Landis, C. E., Lovegreen, L. D., & Trapl, E. S. (2003). Parental monitoring, negotiated unsu- pervised time, and parental trust: The role of perceived parenting practices in adolescent health risk behaviors. Journal of Adolescent Health, 33, 60-70.

Botvin, G. J., Baker, E., Dusenbury, L., Botvin, E. M., & Diaz, T. (1995). Long-term follow-up results of a randomized drug abuse prevention trial with white middle-class population. Journal of the American Medical Association, 273, 1106-1112.

D'Amico, E. J., & Fromme, K. (2002). Brief prevention for adolescent risk taking behavior. Addiction, 97, 563-574.

Gardner, W., Murphy, M., Childs, G., Kelleher, K., Pagano, M., Jellinek, M., McInerny, Wasserman, R. C., Nutting, P., & Chiapetta, L. (1999). The PSC-17: A brief pediatric symptom checklist with psychosocial problem subscales. A report from PROS and ASPN. Ambulatory Child Health, 5, 225-236.

Glantz, M. D. (2002). Introduction to the special issue on the impact of child psychopathology interventions on subsequent substance abuse: pieces of the puzzle. Journal of Con- sulting and Clinical Psychology, 70, 1203-1206.

Guyll, M., Spoth, R. L., Chao, W., Wickrama, K. A. S., & Rus- sell, D. (2004). Family-focused preventive interventions: Evaluating parental risk moderation of substance use tra- jectories. Journal of Family Psychology, 18, 293-301.

Johnson, S. B., & Millstein, S. G. (2003). Prevention opportu- nities in health care settings. American Psychologist, 58, 475-481.

Johnston, L. D., O'Malley, P. M., Bachman, J. G., & Schulen- berg, J. E. (2004). Monitoring the Future: National survey results on adolescent drug use, 2003. (NIH Publication No. 04-5506). Bethesda, MD: National Institute on Drug Abuse.

Kraemer, H. C., Wilson, G. T., Fairburn, C. G., & Agras, W. S. (2002). Mediators and moderators of treatment effects in randomized clinical trials. Archives of General Psychiatry, 59, 877-883.

Kumpfer, K. L., & Alvarado, R. (2003). Family-strengthening approaches for the prevention of youth problem behaviors. American Psychologist, 58,457-465.

Lochman, J. E., & van den Steenhoven, A. (2002). Family- based approaches to substance abuse prevention. Journal of Primary Prevention, 23, 49-114.

McMahon, R. J., & Forehand, R. L. (2003). Helping the non- compliant child (2nd ed.). New York: The Guilford Press.

McMahon, R. J., & Wells, K. C. (1998). Conduct problems. In E. J. Mash & R. A. Barkley (Eds.), Treatment of childhood disorders (2nd ed., pp. 111-207). New York: The Guilford Press.

Murphy, M. J., Arnett, H. L., Bishop, S. J., Jellinek, M. S., & Reade, J. Y. (1992). Screening for psychosocial dysfunction using the Pediatric Symptom Checklist. Clinical Pediatrics, 31,660-667.

Myers, M. G., Brown, S. A., Tare, S., Abrantes, A., & Tomlinson, K. (2001). Toward brief interventions for adolescents with substance abuse and comorbid psychiatric problems. In P. M. Monti, S. M. Colby, & T. M. O'Leary (Eds.), Adolescents, alcohol, and substance use: Reaching teens through brief interventions (pp. 275-296). New York: The Guilford Press.

Ozer, E. M., Park, M. J., Paul, T., Brindis, C. D., & Irwin, C. E. (2003). America's adolescents: Are they healthy? San Fran- ciso: University of California, San Francisco, National Ado- lescent Health Information Center.

Peterson, A. V., Kealey, K. A., Mann, S. L., Marek, P. M., & Sarason, I. G. (2000). Hutchinson Smoking Prevention Project: Long term randomized trial in school-based tobacco use prevention--Results on smoking. Journal of the National Cancer Institute, 92, 1979-1991.

Phares, V. (1996). Fathers and developmental psychopathology. New York: Wiley.

Preacher, K. J., Curran, P. J., & Bauer, D. J. (2004). Probing interactions in multiple linear regression, latent curve analysis, and hierarchical linear modeling: Interactive calculation tools for establishing simple intercepts, simple slopes, and re- gions of significance, www.unc.edu/-preacher/interact/index.

Rothbaum, F., & Weisz, J. R. (1994). Parental caregiving and child externalizing behavior in nonclinical samples: A meta- analysis. Psychological Bulletin, 116, 55-74.

Stevens, M. M., Olson, A. L., Gaffney, C. A., Tosteson, T. D., Mott, L. A., & Starr, P. (2002). A pediatric, practice-based, randomized trial of drinking and smoking prevention and bicycle helmet, gun, and seatbelt safety promotion. Pediat- rics, 109, 490-497.

Weisz, J. R., Weiss, B., Han, S. S., Granger, D. A., & Morton, T. (1995). Effects of psychotherapy with children and adolescents revisited: A meta-analysis of treatment outcome studies. Psychological Bulletin, 117, 450-468.

RECEIVED: April 9, 2004 ACCEPTED: December 18, 2004

a family-focused randomized controlled trial to prevent adolescent alcohol and tobacco use: the...

Documents