This is a multicenter, randomized controlled trial of negative ion generation versus light-emitting diode phototherapy for seasonal affective disorder. Participants appropriate for the study are subjects with a DSM IV diagnosis of Major Depression, with seasonal pattern, winter type. Subjects were seen at Yale University,New Haven,CT University of British Columbia,Vancouver,BC Groningen University Hospital,Groningen, The Netherlands, Royal Ottawa Hospital, Ottawa,Ontario, McGill University, Montreal,Quebec, University Hospital,Saskatoon, Saskatchewan. The trial is 4 weeks in duration.