Using Bright Light Therapy Beyond Seasonal Affective Disorder

The efficacy of bright light therapy to treat seasonal affective disorder (SAD) is firmly established, and researchers have expanded their investigations into further applications of this approach. Studies in the area of chronotherapeutics have found evidence that additional methods of manipulating circadian rhythms may help treat depression, while providing more support for the use of bright light therapy (BLT).

BLT “can be an important and effective treatment of depression, with more rapid onset than anti-depressant medication and minimal side effects,” Richard S. Schwartz, MD, an associate professor of psychiatry at Harvard Medical School and co-founder of GoodLux Technology, told Psychiatry Advisor.

“It ‘phase-advances’ a patient’s circadian rhythm — effectively making his or her biological day start earlier — by stimulating specialized receptors in the retina with links to the suprachiasmatic nuclei in brain,” he added, which essentially comprise the master clock of our bodies. This results in reduced levels of melatonin and increased production of serotonin.  

Research shows that BLT, also sometimes called phototherapy, is effective not only for SAD, but also for non-seasonal unipolar and bipolar depression.

“A landmark review¹ by the American Psychiatric Association in 2005 brought much greater attention and legitimacy to bright light therapy for non-seasonal depression,” Mark Oldham, MD, an assistant professor of psychiatry at Yale School of Medicine, told Psychiatry Advisor. “Since then, several publications have supported its efficacy for non-seasonal depression.”

In a randomized, double-blind, placebo- and sham-controlled trial² reported online last month in JAMA Psychiatry, 122 adults with non-seasonal major depressive disorder (MDD) were randomly assigned to groups consisting of treatment with light therapy, fluoxetine, a combination of the two or placebo. At the end of the eight-week study period, the group showing the most improvement on the Montgomery-Asberg Rating Scale (MADRS) was the one treated with a combination of BLT and fluoxetine, followed by the BLT group.