The objectives of this prospective study were to investigate the influence of comorbid disorders and that of continuation light treatment on remission rates and on a subsequent onset of a depressive episode in outpatients (n = 20) with winter depression. The effects of light treatment were evaluated by the structured clinical interviews and by the self-ratings of mood scored monthly for a follow-up period of 1 year. The remission rates of the patients (n = 8) who proceeded light treatment until the late winter were not significantly different from those of the patients (n = 6) who stopped treatment early during the winter. A more extensive variation in the rates during the year was observed in the former group of patients among whom the comorbid avoidant personality was more frequent, indicating an increased risk of an earlier onset of a depressive episode.