Brain Similarity as a Protective Factor in the Longitudinal Pathway Linking Household Chaos, Parenting, and Substance Use.

Background: Socioecological factors such as family environment and parenting behaviors contribute to the development of substance use. While biobehavioral synchrony has been suggested as the foundation for resilience that can modulate environmental effects on development, the role of brain similarity that attenuates deleterious effects of environmental contexts has not been clearly understood. We tested whether parent-adolescent neural similarity-the level of pattern similarity between parent-adolescent functional brain connectivity representing the level of attunement within each dyad-moderates the longitudinal pathways in which household chaos (a stressor) predicts adolescent substance use directly and indirectly via parental monitoring.

Methods: In a sample of 70 parent-adolescent dyads, similarity in resting-state brain activity was identified using multipattern connectivity similarity estimation. Adolescents and parents reported on household chaos and parental monitoring, and adolescent substance use was assessed at a 1-year follow-up.

Results: The moderated mediation model indicated that for adolescents with low neural similarity, but not high neural similarity, greater household chaos predicted higher substance use over time directly and indirectly via lower parental monitoring. Our data also indicated differential susceptibility in the overall association between household chaos and substance use: Adolescents with low neural similarity exhibited high substance use under high household chaos but low substance use under low household chaos.

Conclusions: Neural similarity acts as a protective factor such that the detrimental effects of suboptimal family environment and parenting behaviors on the development of adolescent health risk behaviors may be attenuated by neural similarity within parent-adolescent bonds.