Effects of Tryptophan Depletion vs Catecholamine Depletion in Patients With Seasonal Affective Disorder in Remission With Light Therapy

Abstract

The beneficial effects of light therapy in the treatment of seasonal affective disorder are reversed by both tryptophan depletion and catecholamine depletion. These findings confirm previous work showing that serotonin plays an important role in the mechanism of action of light therapy and provide new evidence that brain catecholaminergic systems may also be involved.