Treatment of seasonal affective disorders

Seasonal affective disorder (SAD) is a subform of major depressive disorder, recurrent, or bipolar disorder with a regular onset of depressive episodes at a certain time of year, usually the winter. The treatment of SAD is similar to that of other forms of affective disorder, except that bright light therapy is recommended as the first-line option. Light therapy conventionally involves exposure to visible light of at least 2500 lux intensity at eye level. The effects of light therapy are thought to be mediated exclusively by the eyes, not the skin, although this assumption has not yet been verified. Morning light therapy has proven to be superior to treatment regimens in the evening. Response rates to light therapy are about 80% in selected patient populations, with atypical depressive symptoms being the best predictor of a favorable treatment outcome. Data from randomized, controlled trials suggest that antidepressants are effective in the treatment of SAD. Three double-blind, placebo-controlled trials have been conducted showing promising results for the selective serotonin reuptake inhibitors (SSRIs) sertraline and fluoxetine, as well as for moclobemide, a reversible inhibitor of monoamine oxidase A.