A comparison of personality function among patients with seasonal depression, nonseasonal depression, and nonclinical participants.

Although a large body of research has accumulated concerning the relationship between nonseasonal depression and personality, comparatively few studies have examined the relationship between seasonal affective disorder (SAD) and personality. This study compared dimensional aspects of personality in patients diagnosed with SAD (N = 60), nonseasonal depression (N = 273), and nonclinical controls (N = 297) using the Dimensional Assessment of Personality Pathology (DAPP-BQ; Livesley & Jackson, in press). Analysis by ANCOVA indicated that significant between-group differences occurred in several of the 18 DAPP-BQ dimensions, with patients with SAD exhibiting personality psychopathology that was intermediate between the nonclinical sample and patients with nonseasonal depression. The results demonstrated that the traits associated with seasonal and nonseasonal depression differ in degree, not kind.