Phototherapy in individuals with and without subsyndromal seasonal affective disorder.

Antidepressant and energizing effects of bright light exposure (phototherapy) have been widely reported to occur in patients with seasonal affective disorder. We have attempted to evaluate whether other segments of the population might benefit from phototherapy, most notably individuals with subsyndromal seasonal affective disorder, as well as healthy individuals with no winter difficulties (controls). We have studied 20 subjects in each of these two categories and have found that bright artificial light did not alter mood and behavior in controls. In contrast, individuals with subsyndromal seasonal affective disorder responded favorably to treatment with bright environmental light. A dose of 5 hours of bright light exposure, divided between morning and evening, was more effective than 2 hours of exposure. This finding may have practical implications for establishing optimal environmental lighting conditions for those individuals whose winter difficulties do not meet criteria for seasonal affective disorder.

Phototherapy in subsyndromal seasonal affective disorder (S-SAD) and "diagnosed" controls.

Antidepressant and energizing effects of bright light exposure have been widely reported to occur in patients with seasonal affective disorder (SAD). In order to evaluate whether other segments of the population might also benefit from this treatment, we studied 20 normal individuals with mild SAD-like symptoms (subsyndromal SAD, S-SAD) and 20 with no reported seasonal difficulties (non-S-SAD). Whereas S-SAD individuals benefited from phototherapy, non-S-SAD normals did not. This finding raises the questions of whether a history of seasonal problems might be a marker of vulnerability to affective episodes and if S-SAD individuals might be considered as a high risk population in this regard.