The development and maintenance of adolescent depression

This research examined the longitudinal development of depressive symptoms among young adolescents (mean age 12 years). The first model examined depressive symptoms across 6 months in 315 young adolescents and their mothers, considering the mediation of perceived parenting and its influence on adolescent self-worth. Although parent-reported parental depression was not linked with child-reported perceived parenting, the child's perception of his or her mother as rejecting or less caring was associated with a lower sense of self-worth, which in turn predicted depressive symptoms 6 months later, controlling for initial depression. In the second model, tested across 12 months with 896 young adolescent girls, neuroticism served as a distal vulnerability for depression, conferring a risk of experiencing dependent stressors and negative automatic thoughts which fully mediated the effect of neuroticism on later depression. Initial depressive symptoms also followed this meditational pathway, in a possible maintenance and risk pathway for adolescent depression. Unexpectedly, independent stressors were also predicted by initial depressive symptoms, suggesting possible shared method or genuine environmental factors. Finally, it was proposed that young adolescents at risk of depression will not only display cognitive vulnerabilities contributing to increased depressive symptoms following stressors (cognitive diathesis-stress theory), but also be more likely to experience stressors at least partly dependent on their own behaviour (stress-generation theory). This model was supported with a large (N=756) sample of young adolescents across 6 months, controlling for initial depression. Taken together, this thesis extends previous theories about the aetiology of depression, providing evidence from family, personality and cognitive risk factors to better explain the development of depressive symptoms in early adolescence, with significant implications for intervention and treatment.