Annual Research Review: Beyond the target - understanding crossover effects in family-centered prevention

Preventive interventions frequently find positive effects that were not the original targets of the intervention, called crossover effects. This review aimed to catalog crossover effects of family-centered prevention programs (FCPP). The authors searched prevention program registries, screened 2,556 prevention programs (including duplicates across registries), and reviewed 166 programs against inclusion criteria. Of these 24 FCPPs with crossover effects were cataloged. Seven crossover domains (internalizing, externalizing, suicidal thoughts and behaviors, physical health, academics, high-risk sexual behaviors, and parental depression) were reviewed. Fourteen of the 24 reviewed programs yielded evidence of significant main effects on at least one crossover domain, with several yielding evidence across multiple crossover domains. Understanding the full breadth and reach of preventive interventions, including crossover effects, can increase efficiency and cost-effectiveness of prevention strategies. Most programs reviewed reported more than one crossover effect, and many others are encouraged to test the data for additional benefits. New data harmonization techniques can assist with low base-rate outcomes and smaller subgroup restrictions. Finally, more mechanistic and longitudinal investigations are needed to effectively leverage the FCPPs with the most widespread crossover effects.