 Research procedures will not begin in the AutumnWinter until the subject has a depression rating of at least 20 on the SIGH-SAD Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorders Version; Williams et al., 1988. The SIGH-SAD is a structured clinical interview for rating not only the traditional Hamilton Depression Rating Scale items but also the atypical vegetative symptoms characteristic of SAD. The validity of and reliability of the SIGH-SAD is well-established, and it is the preferred instrument for assessing symptom severity in SAD studies e.g., see Lam Levitt, 1999. A companion instrument, the Hypomania Interview Guide for Seasonal Affective Disorder HIGH-SAD also will be administered. A rater, who will be blind to the treatment condition of the subjects, will administer the SIGH-SAD and HIGH-SAD prior to and for each week during the 3-wk trial. 