Light Therapy as Effective as Fluoxetine for Seasonal Affective Disorder

October 18, 2004

Alison Palkhivala

Oct. 18, 2004 (Montreal) — Light therapy is as safe and effective as fluoxetine for the treatment of seasonal affective disorder (SAD), according to a Canadian randomized trial. Clinicians, therefore, should consider light therapy for patients who may prefer this modality, researchers report.

"It's always a struggle to bring nonpharmacological treatments into mainstream medicine," Raymond W. Lam, MD, FRCPC, FAPA, told Medscape. "...so, we try to stress that there's a very effective [nonpharmacologic] treatment out there for winter depression — light therapy, and it's a shame that more patients aren't getting access to it because physicians aren't aware of it."

Dr. Lam is a professor and head of the Division of Clinical Neuroscience, Department of Psychiatry at the University of British Columbia (UBC) and director of the Mood Disorders Clinic at UBC Hospital in Vancouver, Canada. He presented the results of his latest trial on the use of light therapy in SAD here at the 54th annual meeting of the Canadian Psychiatric Association.

The currently accepted light therapy for this condition is use of a 10,000 lux white fluorescent lightbox 30 minutes daily in the early morning, usually between 7 and 8 am. Previous randomized controlled trials have demonstrated the benefits of light therapy and selective serotonin reuptake inhibitor (SSRIs) such as fluoxetine in the treatment of SAD. The question remains, said Dr. Lam, if one is superior to the other with respect to efficacy and adverse effects.

"Because of the lack of data and the importance of the clinical question, we embarked on a large, randomized clinical trial to directly compare light treatment with fluoxetine," Dr. Lam said during his talk.

For this multicenter trial, 96 patients with moderate to severe SAD were randomized to receive eight weeks of treatment with either 20 mg of fluoxetine daily plus 30 minutes daily of placebo 100 lux white fluorescent light in the early morning or a placebo pill plus 30 minutes daily of active 10,000 lux white fluorescent light in the early morning. Patients were studied over three winter seasons. "This is the longest light treatment study in the field," Dr. Lam said.

Patients were diagnosed using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for SAD, and their depressive symptoms were measured using Hamilton Rating Scales (HAM) for Depression: HAM-17 and HAM-24. Participants in the trial had HAM-17 scores greater than 20 or HAM-24 scores greater than 22 to ensure they had moderate to severe SAD. Adverse effects were assessed using a structured questionnaire that included specific questions about individual adverse events.

During eight weeks of treatment, the mean change in HAM-24 scores was similar for both groups of patients, except for a significantly superior improvement in the light therapy group at week 1 ( P <= .01).

After eight weeks, 67% of patients in both groups had responded to therapy, defined as a greater than 50% improvement in HAM-24 score. Also, 50% of patients in the light therapy group and 54% in the fluoxetine group experienced remission, defined as having a HAM-24 score less than 9. Results were similar when the most severely depressed patients were examined separately, which refutes suggestions in the literature that light therapy is only effective for more mild cases of SAD.

"Based on the primary outcome measures, there was no difference in the effect between light treatment and fluoxetine over the course of the eight weeks," said Dr. Lam.

Patients in both groups tolerated their therapies well. The only statistically significant differences were slightly higher incidences of agitation, chest tightness, palpitations, sleep disturbance, and nausea in the fluoxetine group. Overall, similar numbers of patients experiencedat least one treatment-emergent adverse effect in each group.

Given their similar efficacy and tolerability, Dr. Lam suggested that factors to consider when selecting light vs drug therapy for patients with SAD include patient preference, convenience, and cost.

A free downloadable resource package for physicians on how to use light therapy in clinical practice is available at Dr. Lam's institution's Web site at http://www.ubcsad.ca. It includes information on how to obtain and use a lightbox, as well as patient education and assessment materials and additional information about the effectiveness of light therapy.

The study was funded by the Canadian Institutes of Health Research.

CPA 54th Annual Meeting: Paper PS7D. Presented Oct. 16, 2004.

Reviewed by Gary D. Vogin, MD

Alison Palkhivala is a freelance writer for Medscape.

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