Although depression rates increase rapidly in adolescence, the mechanisms behind

this development are not fully understood. This Book examined the role of several risk

factors for adolescent depression with a focus on risk-taking, reward-seeking, early

childhood temperament and social interactions. Two samples were used across four

empirical papers. First, a sample of behaviourally inhibited (BI) and uninhibited (BUI)

preschool children (n = 70). Second, a sample of adolescents initially recruited and

classified at BI and BUI at age 4. Paper 1 examined how the temperamental constructs of

BI and effortful control related to risk-taking. Effortful control, but not BI, at age 4 was

related to reward focused risk-taking on the Balloon Analogue Risk Task (BART). Paper 2

examined the association between BI in childhood, risk-taking and depressive symptoms in

adolescence, including how risk-taking as measured by the BART may present a potential

risk pathway. An interaction between BI and risk-taking was associated with depressive

symptoms in early adolescence. Due to the salience of peers in adolescence and the role

that peer interactions might play in risk for adolescent depression, Paper 3 further explored

risk-taking by developing a novel measure of social risk-taking and examining the

association between scores on this measure and depressive symptoms over a 6-month

period. A bidirectional relationship between social risk-taking and depressive symptoms

was found. In addition, social acceptance partially mediated the relationship between

depressive symptoms and social risk-taking. Finally, Paper 4 focused on reward-seeking

using an adapted effort-reward task. No overall difference was found between early

adolescents with or without symptoms of depression in their motivation to view a

rewarding cartoon. Nevertheless, the task shows promise for future work in this area.

Taken together, the results of this Book present unique information about adolescent

depression and the risk factors of temperament, risk-taking, reward-seeking and social risktaking.