Can developmental changes in inhibition and peer relationships explain why depressive symptoms increase in early adolescence?

Why do depressive symptoms increase during adolescence? Because inhibition and poor peer relationships predict adolescents' depressive symptoms concurrently, we hypothesized that adolescents who cope with the stresses of this period by becoming increasingly inhibited may experience increasing depressive symptoms both directly and due to increased difficulty with peers. Longitudinal data from 904 participants, (52% female; 87% Caucasian, 5% Hispanic, 4% African-American, 4.6% other) from the NICHD Study of Early Child Care were examined when youth were in sixth and ninth grades. Path analyses revealed a direct effect of inhibition: Youth who became more inhibited reported increasing depressive symptoms. Indirect effects showed that they also experienced declines in friendship quality and popularity, which in turn led to increases in depressive symptoms. Findings suggest that increasing inhibition as an adaptation to the stresses of adolescence, and particularly its impact on popularity, is a risk factor for increases in depressive symptoms.