Personality structure in patients with winter depression, assessed in a depression-free state according to the five-factor model of personality

Background: Depressive disorders are often associated with abnormalities of personality. This has also been found in Seasonal Affective Disorder, Winter Depression type (W-SAD), although relatively few and small studies have been done on this disorder so far, and mainly in the depressed phase. The aim of this study was to explore the personality structure and its possible background and clinical correlates in a larger group of patients with W-SAD, assessed in a non-depressed state, in the Five-Factor (or ‘Big Five’) model of personality paradigm. Methods: 82 persons (87% of those asked) with diagnosed W-SAD, most of them originally self-referred, who had previously received light treatment at our unit, completed a Norwegian version of an inventory yielding the personality factors Agreeableness, Surgency, Conscientiousness, Emotional stability, and Openness to experience. Results: Compared to a Norwegian reference group, the mean scores of the W-SAD patients were significantly lower on the factors agreeableness, surgency and emotional stability, and significantly higher on conscientiousness. However, very few patients had scores outside the reference range. The personality factors do not seem to be associated with the core physiological manifestations of winter depression, but rather with the psychic aspects, and are poor predictors of response to light treatment. Limitations: Some reservations should be made as to the generalisability of the findings to SAD patients in general. Thus, increased conscientiousness may reflect help-seeking behaviour. Conclusions: Personality structure does not seem to predict occurrence of physiological reactions to lack of adequate daylight in autumn/winter, and is a poor predictor of improvement after light treatment, but may predict the associated psychic symptomatology.