Some people with seasonal affective disorder (SAD) can be successfully treated with exposure to bright light. In one study, 57% of 191 people with SAD responded to light therapy. In another study, light therapy was comparable in effectiveness to antidepressant therapy but worked faster and caused fewer side effects. And in a major review of 173 published studies, bright-light therapy yielded substantial relief for both SAD and mild to moderate depression that was not linked to seasonal changes.
Light therapy involves sitting in front of a bank of full-spectrum fluorescent lights for 30 to 60 minutes each day. Improvement can often be seen within a few days, with symptoms disappearing after two to three weeks. Continued light therapy is needed to prevent a relapse. Although commercially available light boxes are advertised for depressed people, these devices are not approved by the FDA. Light therapy should be used only with your doctor’s guidance, as it can cause side effects when used improperly. For instance, light therapy may trigger manic symptoms in people who have bipolar disorder.