Authors' objectives:

This report aims to assess the effectiveness of light therapy for the treatment of seasonal affective disorder (SAD).

Authors' results and conclusions: Design problems, including small sample size, inadequate placebo controls, lack of blinding, and inconsistencies in timing, intensity, and duration of exposure and length of treatment, have hampered a definitive determination of efficacy since the introduction of light therapy as a treatment for SAD. However, several recent studies have attempted to overcome some of these design limitations and have presented evidence that light therapy appears to be an effective treatment for SAD. Combinations of the three components of light therapy, that is, timing, intensity and duration, can affect the outcome of treatment. None of the studies have compared light therapy with other potentially active treatments, such as antidepressant medication and/or psychotherapy. Furthermore, long-term efficacy has not been established, and the intensity-response relationship, the optimal treatment schedule, and the long-term safety of light therapy have also not been clarified.

Authors' recommendations: Light therapy continues to be an investigational treatment. The Food and Drug Administration (FDA) has not yet given clearance to market light boxes in the U.S. for the treatment of SAD nor does the Health Care Financing Administration (HCFA) cover the costs associated with using light therapy. Although, the Agency for Health Care Policy and Research (AHCPR), in guidelines published during 1993, provided light therapy a qualified recommendation under specific conditions. Both the FDA and the AHCPR (see recommendations) state that light therapy should be administered to properly diagnosed patients (who have no psychotic disorder and who are not suicidal) under the guidance of an experienced and trained medical professional. Studies available to date support reasonable beneficial effect of light therapy as a treatment of SAD, where light deprivation is believed to be the causal agent.

Authors' methods: Review

Project Status: Completed

URL for project: http://www.health.state.mn.us/htac/sad.htm

Year Published: 2001

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Health Technology Advisory Committee

Contact Address: Queries should be referred to the Minnesota Department of Health (http://www.health.state.mn.us/)

Copyright: Health Technology Advisory Committee