Atypical depressive symptoms in seasonal and non-seasonal mood disorders.

The authors examined the rates of atypical depression and prevalence of specific atypical symptoms in patients with seasonal versus non-seasonal depression. Fifty-three patients with seasonal affective disorder (SAD) were compared to 54 patients with non-seasonal major depressive disorder (MDD) using the atypical depression diagnostic scale (ADDS). SAD patients scored significantly higher than non-seasonal MDD patients in hyperphagia and hypersomnia, and significantly lower in interpersonal sensitivity and other rejection avoidance. There was no difference in the rate of ADDS diagnosis of atypical depression. Differences between atypical depression and SAD suggest that they are separate subtypes of depression with an overlapping symptom picture.