Does Light Therapy Work for Non-Seasonal Depression?

April 1, 2016

Bret A. Moore, PsyD, ABPP Board-Certified Clinical Psychologist, San Antonio, TX Dr. Moore has disclosed that he has no relevant financial or other interests in any commercial companies pertaining to this educational activity.

(Lam R et al, JAMA Psychiatry 2016;73(1):56-63)

Many studies have shown that light therapy works for seasonal affective disorder, but does it work for non-seasonal major depression? That’s less clear. Systematic reviews have yielded inconclusive results, in part because prior studies have had methodological weaknesses. A new study with a robust design was just published.

Over a 5-year period, researchers recruited 122 adult patients with non-seasonal major depression between the ages of 19 through 60 from three clinics in Canada. The patients were randomized to 1 of 4 groups: light therapy alone, fluoxetine 20 mg plus light therapy (combination treatment), fluoxetine 20 mg plus sham negative ion treatment, and double placebo (placebo pills plus negative ion). Light therapy was given with a 10,000-lux fluorescent light box for 30 minutes daily in the early morning. The study lasted 8 weeks, and 106 participants completed it. The primary outcome measure was change in the Montgomery-Åsberg Depression Rating Scale (MADRS); secondary outcomes included response and remission rates.

At study conclusion, both light therapy and combination therapy were superior to placebo; however, combination therapy beat placebo more consistently. Whereas light therapy yielded lower MADRS scores than placebo, combination therapy bested placebo on MADRS scores, response rates, and remission rates. Surprisingly, fluoxetine was not significantly better than placebo; the authors attribute this to small sample size.

Here are the numbers: Average improvements in MADRS scores were 16.9 (combined fluoxetine and light), 13.4 (light), 8.8 (fluoxetine and sham light), and 6.5 (placebo). Response rates (defined as ≥ 50% drop in MADRS score) for combined treatment, light, fluoxetine, and placebo were 76%, 50%, 29% and 33%, respectively. Remission rates (defined as MADRS score ≤ 10) were 59%, 44%, 19% and 30%.

TCPR’s Take
This is probably the best designed clinical trial of light therapy for non-seasonal depression to date, and the results endorse both light monotherapy and combination light and fluoxetine, with the combination being possibly more robust. The bottom line is that, at least for depressed patients in the higher latitudes, you should consider recommending light therapy either alone or in combination with SSRIs.

General Psychiatry