Abstract/Summary

Adolescence is a distinct phase of development, with a high incidence of depression. Despite this, adolescent depression has been somewhat neglected by researchers and treatment is largely based on adult research. The aim of the five papers in this thesis is to describe and understand characteristics of depressed adolescents that could be addressed in psychological treatment. These specifically relate to clinical presentation and cognitive biases. Paper 1 describes the characteristic of 100 adolescents referred and assessed for depression. Fewer than 50% met diagnostic criteria for depression. For those with a diagnosis, the most common depression symptoms were low mood or irritability, suicidal thoughts, cognitive disturbances, and sleep disturbances. There was no relationship between adolescent and parent report of the young person’s symptoms. Paper 2 presents a review of cognitive biases in adolescent depression. Cognitive biases may characterise adolescents with depression, but the limited numbers of studies and methodological problems make confident conclusions difficult. Some of these limitations are addressed in the remaining three papers with a focus on interpretation and memory biases. An interpretation bias measure for depression was adapted for adolescents and had good psychometric properties (Paper 3). Using this measure in Paper 4, adolescents with depression displayed a negatively biased interpretation of ambiguous situations compared to other clinically referred adolescents and community groups of adolescents. In Paper 5, self evaluation and recall memory bias were examined. Compared to non-depressed adolescents, adolescents with depression rated themselves using more negative and fewer positive adjectives, and recalled fewer positive adjectives (Paper 5). Broadly these data suggest that elements of the cognitive model of depression do apply to adolescents with depression. However, depressed young people present with a range of symptoms, including high levels of risk and many of these are not fully addressed by cognitive behavioural therapy for depression.