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

Early adolescence is a period marked by increases in internalizing problems, particularly depression. In childhood, the rates of depressive symptomatology are between .6% and 1.7%, but by adolescence, rates rise to 8.0%. Two key correlates of adolescent depression are behavioral inhibition and poor peer relations. Yet, it is unclear whether these factors simply co-occur with depressive symptoms or are instrumental across development in regulating them. In this study, using data from the NICHD Study of Early Child Care, we examine whether increases in inhibition in late childhood may undermine peer relationships in predicting increases in adolescent depressive symptoms. Specifically, we test whether inhibition promotes depressive symptoms by undermining two aspects of peer relationships – popularity and friendship quality. Findings revealed that increases in inhibition from childhood to adolescence lead to increases in adolescent depressive symptoms. Decreases in popularity mediated the relation of inhibition, friendship quality and increases in adolescent depressive symptoms.