Bidirectional Associations Between Physical Activity and Internalizing Symptoms in Early Adolescence: A Four-Wave...

BackgroundRates of mental illness in adolescents are increasing at an alarming rate. At the same time, youth participation in physical activity is continually declining. International public health guidelines recommend that children spend at least 60 min/day in moderate-to-vigorous physical activity for optimal development of brain health. This study aimed to disentangle within-person effects of physical activity on mental health symptoms from stable, between-person differences using a four-wave random-intercepts cross-lagged panel model (RI-CLPM).MethodsData from the longitudinal Adolescent Brain Cognitive Development (ABCD) Study were used to follow pre-adolescent children (N = 6361) across development (10-14.2 years old). Physical activity was measured by youth-report. Internalizing and externalizing mental health behaviors were measured by the parent-reported Child Behavior Checklist. Bidirectional relationships between mental health and physical activity were assessed using RI-CLPM.ResultsFor internalizing symptoms, cross-lagged (within-person) random effects showed that higher physical activity at year 2 predicted fewer internalizing symptoms at year 3 (β= -0.037 [-0.062 to -0.012]), and from year 3 to year 4 (β = -0.045 [-0.068 to -0.022]). More internalizing symptoms at baseline predicted less physical activity from year 2 to year 3 (β = -0.076 [-0.125 to -0.027]), and from year 3 to year 4 (β = -0.075 [-0.118 to -0.031]). For externalizing symptoms, there were no significant cross-lagged or between-person effects.ConclusionIn this large, multi-wave longitudinal cohort, more physical activity was associated with fewer internalizing symptoms across early adolescent development. Additionally, higher internalizing symptoms were associated with lower physical activity across development. No associations were found with externalizing symptoms. Findings suggest that physical activity may alleviate internalizing symptoms during early adolescence, underscoring the need for promoting adherence to international physical activity guidelines in the complex management of adolescent mental health.