Maternal History of Major Depression, Social Support from Peers, and Children's Risk for Self-Injurious Thoughts and Behaviors.

Self-injurious thoughts and behaviors (SITBs), encompassing both nonsuicidal self-injury and suicidality, are a growing public health concern in youth. Although maternal depression is a well-established risk factor for psychopathology in offspring, less is known about protective factors that may mitigate this risk. Peer social support, particularly during the transition to adolescence, may play a critical role in reducing risk for SITBs, yet limited research has examined the potential impact of different domains of peer influence (e.g., close friends versus classmates) as specific and distinct facets of the peer environment. In a two-year longitudinal study, we assessed SITBs in 215 children (ages 8-14), half of whom had mothers with a history of major depressive disorder (MDD) during their child's life. We hypothesized that maternal MDD would predict increased risk of SITBs in children but that higher levels of peer social support would buffer this effect. Survival analyses confirmed that children of mothers with MDD were over twice as likely to develop SITBs during the follow-up. Importantly, higher levels of social support from classmates uniquely predicted reduced risk for SITBs in children, even after accounting for the influence of maternal MDD history. Our findings highlight the role of broad peer environments in protecting against SITBs in youth. These results underscore the importance of school-based interventions that foster social inclusion as potential preventive measures for SITBs.