Prevention programs that strengthen parenting and family functioning have been found to reduce poor behavioral outcomes in adolescents, including substance use, HIV risk, externalizing and internalizing problems. However, there is evidence that not all youth benefit similarly from these programs. Familias Unidas is a family-focused intervention designed to prevent substance use and sexual risk among Hispanic youth and has recently demonstrated unanticipated reductions in internalizing symptoms for some youth. This paper examines variation in intervention response for internalizing symptoms using individual-level data pooled across four distinct Familias Unidas trials: (1) 266 eighth grade students recruited from the general school population; (2) 160 ninth grade students from the general school population; (3) 213 adolescents with conduct, aggression, and/or attention problems; and (4) 242 adolescents with a delinquency history. Causal inference growth mixture modeling suggests a three-class model. The two largest classes represent youth with low (60 %) and medium (27 %) internalizing symptoms at baseline, and both intervention and control participants show reductions in internalizing symptoms. The third class (13 %) represents youth with high levels of baseline internalizing symptoms who remain at steady levels of internalizing symptoms when exposed to the intervention, but who experience an increase in symptoms under the control condition. Female gender, low baseline levels of parent-adolescent communication, and older age were associated with membership in the high-risk class. These synthesis analyses involving a large sample of youth with varying initial risk levels represent a further step toward strengthening our knowledge of preventive intervention response and improving preventive interventions.
Keywords: Adolescent; Family; Hispanic; Integrative data analyses (IDA); Internalizing symptoms; Prevention; Variation in response.