Predictors of response to phototherapy in seasonal affective disorder.

We examined data from 44 women with seasonal affective disorder (SAD) to determine whether any demographic, diagnostic, or symptomatic characteristics would be predictive of a favorable response to phototherapy. Preexistent hypersomnia was particularly associated with lessening of depression after phototherapy. In contrast to a report elsewhere, both "typical" and "atypical" depressive symptoms correlated with improvement after phototherapy.