Dr. Young's LabCognitive vulnerability to depression in seasonal affective disorder
Justin Enggasser, Dissertation (2005).
According to Young's dual vulnerability model, individuals who are at risk for seasonal affective disorder (SAD) possess two separate vulnerabilities. The first is a vulnerability to experience large seasonal fluctuations in vegetative functions (e.g., sleep, appetite, energy), referred to as "seasonality." The second is a vulnerability to developing mood and cognitive symptoms of depression in response to the stress of the vegetative symptoms. Consequently, a cognitive vulnerability to depression may differentiate highly seasonal individuals who do and do not develop the mood and cognitive symptoms of depression required to meet full criteria for a diagnosis of SAD. The purpose of the present study was to validate Young's dual vulnerability model by testing the hypothesis that higher levels of dysfunctional attitudes, a more negative attributional style, and a more ruminative response style are associated with more severe mood and cognitive symptoms among individuals with moderate to high levels of vegetative seasonality. To test the hypothesis, participants with a history of at least a moderate level of vegetative symptom seasonality were recruited from the community. Cognitive vulnerability to depression was assessed during summer months while participants were non-symptomatic. Participants were administered the attributional style questionnaire and response styles questionnaire prior to the induction of a negative mood, and the dysfunctional attitudes scale was administered before and after mood induction. Results revealed that, among individuals who experience vegetative seasonality, those with more dysfunctional attitudes, a more internal attributional style for negative events, and a more ruminative response style reported experiencing more severe mood and cognitive symptoms of depression during the winter. These results provide support for Young's dual vulnerability model, and suggest that cognitively oriented psychological interventions may be useful as adjunctive or alternative treatments for SAD.