Familias Unidas Prevents Youth Internalizing Symptoms: a Baseline Target Moderated Mediation (BTMM) Study.

Family-based preventive interventions have been found to prevent youth internalizing symptoms, yet they operate through diverse mechanisms with heterogeneous effects for different youth. To better target preventive interventions, this study examines the effects of the Familias Unidas preventive intervention on reducing internalizing symptoms with a universal sample of Hispanic youth in a real-world school setting (i.e., effectiveness trial). The study utilizes emerging methods in baseline target moderated mediation (BTMM) to determine whether the intervention reduces internalizing symptoms through its impact on three distinct mechanisms: family functioning, parent stress, and social support for parents. Data are from a randomized controlled effectiveness trial of 746 Hispanic eighth graders and their parents assessed at baseline, 6-, 18-, and 30-month post-baseline. BTMM models examined three moderated mechanisms through which the intervention might influence 30-month adolescent internalizing symptoms. The intervention decreased youth internalizing symptoms through improvements in family functioning in some models, but there was no evidence of moderation by baseline level of family functioning. There was some evidence of mediation through increasing social support for parents for those intervention parents presenting with lower baseline support. However, there was no evidence of mediation through parent stress. Post hoc analyses suggest a possible cascading of effects where improvements in support for parents strengthened parental monitoring of youth and ultimately reduced youth internalizing symptoms. Findings support the intervention's effects on internalizing symptoms in a universal, real-world setting, and the value of BTMM methods to improve the targeting of preventive interventions. ClinicalTrials.gov Identifier: NCTO1038206, First Posted: December 23, 2009.