Light therapy may treat more than just seasonal affective disorder -- when used alone or in conjunction with antidepressants in a randomized trial, it proved to be effective and well-tolerated for those with major depressive disorder, according to an online report in JAMA Psychiatry.

In an 8-week trial in Canada, Montgomery-Asberg Depression Rating Scale (MADRS) scores improved more in patients with nonseasonal major depression who received light therapy alone and with the antidepressant fluoxetine (Prozac) than in those assigned to treatment with both a placebo device and placebo pills, according to Raymond Lam, MD, of the University of British Columbia, and colleagues.

Lam and colleagues randomized 122 patients to 8 weeks of treatment to light therapy (30 minutes/daily exposure to a fluorescent light box as soon as possible after awakening) and placebo pill (n=32); fluoxetine (20 mg/daily) and placebo device (a negative ion generator, n=31); combination light and fluoxetine treatment (n=29); or placebo device and placebo pill (control; n=30). MADRS was administered before and after the treatment.

Those who received both light therapy and fluoxetine had the highest change in score, at 16.9 points (SD 9.2). In those who received light therapy alone, the change in score was 13.4 (SD 7.5), compared with 8.8 (SD 9.9) in those who received placebo -- with the differences between both light-therapy groups and the control group reaching statistical significance, whereas there was not a significant difference between fluoxetine monotherapy and control.

Response (as measured by a >50% reduction in MADRS score) was achieved by 76% of those using combination of light therapy and fluoxetine, half of those receiving light therapy and placebo, 29%of those receiving fluoxetine and placebo, and 33% of those receiving placebo.

Remission from depressive symptoms, measured as a MADRS score <10 at endpoint, was achieved by 58% of those using the combination of light therapy and fluoxetine, 44% for light therapy and placebo, 19% for fluoxetine, and 30% for placebo.

The authors noted that study limitations included a small sample size with "limited power to detect clinically significant differences between active conditions." In addition, as the researchers studied fixed dosages for light therapy and fluoxetine, it is possible that higher dosages for both fluoxetine and light may lead to greater response. Also, the study took nearly 5 years to complete because of difficulties in recruitment; the trial was halted in two of five original sites where just five patients were enrolled in a 2-year period.

Lam told MedPage Today, "The results are clear enough, especially for the combination of light therapy and antidepressants, for clinicians to consider light therapy as a treatment option for nonseasonal depression."

He noted that the results for light therapy alone should be repeated to confirm that it is effective, but due to the fact that the treatment is safe and well-tolerated, "it could be considered for those who may prefer it over standard treatments."

Further research, Lam said, should replicate the findings in a larger sample, and explore the role of light therapy for major depression. "For example, how long should one keep using the lights after feeling better?" He also noted that the treatment parameters for light therapy treatment of MDD may not be the same as they are for SAD, something that could be determined through research.