Objective: To concisely review the etiology and current treatment modalities of seasonal affective disorder (SAD).
Data sources: A MEDLINE search (1966-1999) was performed using the search term "seasonal affective disorder." The search was subsequently focused to "drug therapy" with limits of human studies and English-language papers. The search term "light therapy" was combined with "seasonal affective disorder."
Study selection and data extraction: Articles discussing the epidemiology and treatment of SAD were independently examined by each author. Additional literature was reviewed from selected references identified by the original articles.
Data synthesis: SAD most likely results from a deficiency in serotonin. Light therapy remains the therapeutic intervention with the most experience and success. Selective serotonin reuptake inhibitors (SSRIs) have also shown benefit in treating the disorder.
Conclusion: SAD is an important subtype of major depressive disorder. Clinicians should remain vigilant for signs and symptoms of the illness. Successful treatment may include light therapy or antidepressants, particularly SSRIs.