Mechanisms By Which Familias Unidas Prevents Youth Internalizing Symptoms: A Baseline Target Moderated Mediation (BTMM) Study

Introduction. Several family-based preventive interventions are effective in preventing adolescent behavior problems, but research often shows heterogeneity in those effects. Baseline target moderated mediation (BTMM) analyses (Howe, 2017) can identify distinct intervention mechanisms of action (mediators) that differentially operate depending on baseline levels of modifiable, theoretically-informed intervention targets (moderators). These analyses can inform matching interventions to the needs of families. Familias Unidas is a preventive intervention for Hispanic youth hypothesized to reduce youth behavior problems through improvements in family functioning and parent support, as well as reductions in parent stress. The present study utilizes BTMM to determine whether Familias Unidas reduces youth internalizing symptoms through distinct mechanisms among families presenting with specific baseline intervention needs.

Method. Data for these analyses come from a randomized controlled effectiveness trial of the Familias Unidas preventive intervention (n = 746), which targeted Hispanic eighth graders and their parents. Assessments were conducted at baseline, 6-months, 18-months and 30-months. Separate baseline target moderated mediation models were used to examine three potential moderated mechanisms through which Familias Unidas was hypothesized to influence 30-month adolescent internalizing symptoms: family functioning, parent support and parent stress, all assessed at 6-months (post-intervention). Each model examined whether there was an indirect effect of the intervention on internalizing symptoms that differed by baseline level of the mediator.

Results and Conclusions. There was no evidence of baseline moderated mediation on the impact of Familias Unidas on internalizing through family functioning or parent stress. However, there was evidence of BTMM through parent support. The impact of Familias Unidas on 6-month parent support was significantly moderated by baseline levels: greater increases in 6-month parent support were observed for parents with lower baseline levels of support. Higher levels of parent support at 6 months was associated with lower levels of internalizing symptoms at 30-months (b = 0.06, p = .03). Post-hoc analyses supported a cascade effect through parent involvement. Specifically, 6-month parent support was positively associated with parent-reported involvement at 18 months (b = 0.07, p < .001). which in turn was negatively associated with adolescent-reported internalizing symptoms at 30 months (b = -0.26, p = 0.001). Findings indicate that for families who are initially low on parent support, Familias Unidas lowers youth internalizing symptoms through improving parent support which is related to higher levels of parent involvement and subsequently lower levels of youth internalizing symptoms. These findings support further development of more targeted preventive interventions.