Depression is a debilitating mental illness with clear developmental patterns from childhood through late adolescence. Here, we present data from the Gene Environment Mood (GEM) study, which used an accelerated longitudinal cohort design with youth (N = 665) starting in 3rd, 6th, and 9th grades, and a caretaker, who were recruited from the general community, and were then assessed repeatedly via semi-structured diagnostic interviews every 6-months over 3 years (7 waves of data) to establish and then predict trajectories of depression from age 8 to 18. First, we demonstrated that overall prevalence rates of depression over time, by age, gender, and pubertal status, in the GEM study closely match those trajectories previously obtained in past developmental epidemiological research. Second, we tested whether a genetic vulnerability-stress model involving 5-HTTLPR and chronic peer stress was moderated by developmental factors. Results showed that older aged adolescents with SS/SL genotype, who experienced higher peer chronic stress over 3 years, were the most likely to be diagnosed with a depressive episode over time. Girls experiencing greater peer chronic stress were the most likely to develop depression.

During the transition to adolescence, several developmental trends converge to increase the importance of peer relationships, the likelihood of peer-related stressors, and the experience of depressive symptoms. Simultaneously, there are significant changes in parent-child relationships. The current study sought to evaluate whether positive relationship quality with parents continued to serve a protective effect by buffering the relationship between stressful life events, especially peer stress, and increases in depressive symptoms throughout the transition to adolescence. Participants in a large (N = 675), two-site accelerated longitudinal study were recruited in 3rd, 6th, & 9th grade and followed every 3 months for 1 year. At baseline parents and youth reported on parent-child relationship quality, and every three months thereafter reported on their levels of stressors and depressive symptoms. Parent relationship quality moderated the relationship of person-level fluctuations in peer stressors, such that there was a stronger association between peer stressors and increases in depressive symptoms in youth with lower levels of positive parental relationship quality. This effect was specific to peer stressors. These results suggest that low levels of parent relationship quality leave youth particularly vulnerable to the depressogenic effects of peer stressors from childhood through adolescence.

No abstract

Predictors of depressive symptoms may differ before and after the first onset of major depression due to stress sensitization. Dependent stressors, or those to which characteristics of individuals contribute, have been shown to predict depressive symptoms in youth. The current study sought to clarify how stressors’ roles may differ before and after the first depressive episode. Adolescents (N = 382, aged 11 to 15 at baseline) were assessed at baseline and every three months over the course of two years with measures of stressors and depressive symptoms. Semi-structured interviews were conducted every 6 months to assess for clinically significant depressive episodes. Hierarchical linear modeling showed a significant interaction between history of depression and idiographic fluctuations in dependent stressors to predict prospective elevations of symptoms, such that dependent stressors were more predictive of depressive symptoms after onset of disorder. Independent stressors predicted symptoms, but the strength of the association did not vary by depression history. These results suggest a synthesis of stress sensitization and generation processes that might maintain inter-episode depressive symptoms among youth with a history of clinical depression.