Abstract
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). MDFT 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.
