Reducing Trait-Like Externalizing Problems Through School-Based Prevention Programs: A Gene by Intervention Interaction

Introduction: Externalizing behavior problems have been studied extensively in children and adolescents, as they have been shown to have long-term implications in a variety of important outcomes, and thus are a common target in school-based preventive interventions, such as the Good Behavior Game.  While previous research on this program has demonstrated a range of positive outcomes, no studies have explored whether intervention impacts on impulsivity and related externalizing behavior problems are moderated by genetic factors, such as the brain derived neurotrophic factor (BDNF) gene, which has been previously linked with impulsivity.  This study explored for an interaction between the intervention and the BDNF gene using longitudinal data on aggression using a latent trait-state-error model (Kenny & Zautura, 1995).  Latent trait-state-error modeling allowed us to decompose the variance of aggressive behaviors across seven time points into a stable trait component, a changing state component, and an error component, and allowed us to regress predictors on the stable trait component. 

Method: Data come from a randomized controlled trial testing the long-term impacts of the GBG combined with academic enhancements relative to a family-focused intervention and a control condition on behavioral and mental health outcomes through age 24. The sample included 678 urban, primarily African American children who were in first grade classrooms randomized to one of three conditions:  classroom-centered (CC) intervention, which combined the GBG with an enhanced academic curriculum; Family School Partnership (FSP), focused on promoting parental involvement in educational activities and behavior management strategies; or a control condition. Teacher ratings of youth’s externalizing behavior were obtained at baseline and in grades 6-12 via the Teacher Observation of Classroom Adaptation-Revised. SNPs from the BDNF gene were extracted from the genome wide data at ages 19-24.

Results: The latent trait-state-error model analyses suggested that the amount of variance in externalizing symptoms that is accounted for by the stable trait variable increases across development.  Results showed that individuals in either of the interventions are more likely to have lower trait-level aggression from middle school to adolescence.  A significant interaction was observed between a particular profile of the BDNF haplotype (46% of sample) and FSP intervention on aggression (β = -.38, p < .01).

Discussion:  The results from this study have implications in the development of prevention and treatment programs of externalizing problems during childhood and adolescence and shed light on potential generic reasons for variation in program impacts.