PREVENTION OF WINTER SEASONAL AFFECTIVE-DISORDER BY BRIGHT-LIGHT TREATMENT

In patients with winter seasonal affective disorder (SAD) the onset of a depressive episode is probably associated with the decreasing amoun t of light during the autumn. A highly predictable onset of a recurren t depressive episode with seasonal pattern provides a rationale for te sting the efficacy of bright-light treatment as a preventive measure. Twelve out-patients with winter SAD were assigned to start bright ligh t treatment either when they were well, or not to start it until the f irst symptoms of depression had already emerged. The severity of depre ssive symptoms was prospectively rated for a parallel randomized compa rison. Bright light given well in advance of the emerging symptoms pre vented a depressive episode. Clinical remission was significantly more frequent in the former subgroup of the patients in January and in Mar ch. To sum up, bright light can be successfully administered as prophy lactic treatment for the prevention of winter SAD.