Mediating Effects of Healthy Lifestyle Factors on Associations between Mental Health and Functional Outcomes in Early Adolescence

ObjectiveAlthough mental health and healthy lifestyle interventions are associated with functional outcomes in adolescence, the extent to which particular lifestyle factors explain relationships between mental health and outcome are unclear. Here we examined mediating effects of lifestyle factors on relationships between mental health and two functional outcomes measured 2-3 years later as well as the moderating effect of environmental risk factors on mediation strength in early adolescence. MethodsThis study analyzed data from 3 waves of the Adolescent Brain Cognitive Development Study (ages 10-11, 11-12, and 12-13). Mediating effects of sleep quality, screen time, physical activity and Mediterranean diet on the relationships between depression, anxiety, psychotic-like experience (PLE) distress, and total problems with two subsequent functional outcomes (academic functioning and social problems) were examined. Secondary analyses included environmental factors as moderators. ResultsSleep quality mediated 18.5%, 36.3%, 8.3%, and 3.4% of the relationships between depression, anxiety, PLE distress and total problems with academic functioning, respectively. Screen time was the second strongest mediating factor. For social problems, only sleep quality showed > 3% mediation (19.6% - 23.3%). Mediating effects of sleep and screen time on academic functioning decreased as financial adversity increased. Conversely, mediating effects of sleep quality on social problems increased with worsening family conflict, financial adversity, and school environment. ConclusionsThese results suggest that healthy lifestyle factors (in particular sleep quality) may partially explain the associations between mental health and functioning in adolescents and suggest that these effects are modulated by environmental factors. These results may have important implications for future intervention studies.