Gender and Ethnicity as Moderators: Integrative Data Analysis of Multidimensional Family Therapy Randomized Clinical Trials

This study examined gender and ethnicity as moderators of Multidimensional Family Therapy (MDFT) effectiveness for adolescent drug abuse and illustrated the utility of integrative data analysis (IDA; Bauer & Hussong; 2009) for assessing moderation. By pooling participant data from 5 independent MDFT randomized clinical trials (RCTs), IDA increased power to test moderation. Participants were 646 adolescents receiving treatment for drug use, aged 11 to 17 years (M = 15.31, SD = 1.30), with 19% :female (n = 126), 14% (n = 92) European American, 35% (n = 225) Hispanic, and 51% (n = 329) African American. Participants were randomized to MDFT or active comparison treatments, which varied by study. Drug use involvement (i.e., frequency and consequences) was measured at study entry, 6-; and 12-months by a 4-indicator latent variable. Growth curve change parameters from multiple calibration samples were regressed on treatment effects overall and by moderator subgroups. MDFT reduced drug use involvement (p < .05) for all participant groups. Pooled comparison groups reduced drug use involvement only for females and Hispanics (ps < .05). MDET was more effective than comparisons for males, African Americans, and European Americans (ps < .05; Cohen's d = 1.17, 1.95, and 1.75, respectively). For females and Hispanics, there were no significant differences between MDFT and pooled comparison treatments, Cohen's d = 0.63 and 0.19, respectively. MDFT is an effective treatment :for drug use among adolescents of both genders and varied ethnicity with males, African American, and European American non-Hispanic adolescents benefitting most from MDFT.