AbstractDepression has consistently been associated with cognitive deficits, particularly on tasks involving executive function. Depression is also characterised by a self-focused, ruminative thinking style. It has been hypothesised that this ruminative thinking style may deplete limited executive resources, giving rise to inefficient cognitive regulation of emotion and behaviour. Previous research with adults has supported this hypothesis and indicated that, relative to non-depressed controls, those who are low in mood and are induced to ruminate demonstrate impairments in executive function. Whilst some research with adolescents has also supported this finding, this has mainly been correlational in nature. Adolescent-onset depressive disorders represent particularly insidious conditions because of their strong association with chronic and recurrent emotional problems in adulthood; thus, a detailed understanding of the cognitive processes underlying these disorders is essential.
The current study provides the first experimental investigation of the effects of engaging in a ruminative and a concrete processing style on executive function in dysphoric adolescents. The study was conducted with a school-based sample of 46 young people, who scored high or low on a measure of depressive symptoms. Participants completed two experimental conditions, rumination and concrete thinking, in counterbalanced order, as well as a measure of executive function (random number generation) at baseline, and again following each of the experimental conditions.
For the first time, results demonstrated that one facet of executive function (working memory updating) differed significantly at baseline, with dysphoric adolescents demonstrating significantly worse performance than non-dysphoric adolescents, and that this difference was maintained regardless of the thinking style inductions. Contrary to the study’s hypotheses, inhibition ability of either group was not significantly affected by either of the processing style inductions. Potential explanations for these results are discussed, as well as methodological limitations, clinical implications, and potential directions for future research.
|Date of Award
|Patrick Smith (Supervisor)