Major Depression and the Five-Factor Model of Personality

The NEO Personality Inventory (NEO-PI) was administered to a sample of unipolar, nonpsychotic depressed outpatients receiving pharmacotherapy. Fifty-seven patients were assessed on two occasions—at treatment entry (Time 1) and 3 months following initiation of treatment (Time 2). The Neuroticism (N) and Extraversion (E) dimension scores were altered by the depressive episode, whereas the Openness (O), Conscientiousness (C), and Agreeableness (A) dimensions were not altered. The N dimension for the recovered patients at Time 2 was at least 1 standard deviation above that of a normative sample, suggesting that N may be a predisposing factor for major depression. E was the best predictor of treatment outcome.