Light Therapy May Prove Helpful For Non-Seasonal Depression


Light therapy is used effectively to treat Seasonal Affective Disorder (SAD). A subtype of major depression, SAD symptoms appear in the fall with decreasing daylight hours and continue through the winter. Its cause are unknown, but a disruption of circadian rhythm, brought on by reduced sunlight, and changes in levels of the neurotransmitter serotonin and hormone melatonin are suspect. SAD is often diagnosed in those already suffering depression. A new study out of the University of British Columbia in Vancouver finds that, in addition to treating SAD, light therapy is effective in treating non-seasonal depression.

Treatments for major depressive disorder include antidepressant medications and therapy. These treatments are often cost prohibitive and, for some people, medications are ineffective. In some regions, providers of psychotherapy are in short supply. Researchers are continually seeking new treatments for depression, which affects an estimated 350 million people worldwide. The University of British Columbia study, published in the November 2015 issue of JAMA Psychiatry, was conducted to determine the efficacy of light therapy as an additional or alternate treatment for depression.

Dr. Raymond W. Lam and his coauthors conducted an eight-week trial randomly assigning 122 study participants, aged 19-60 years, to one of four groups:

  • Light box exposure and placebo pill;
  • a daily dose of fluoxetine hydrochloride (an antidepressant known by its trade name Prozac) and a placebo light box;
  • a combination of light box and fluoxetine treatment;
  • and a placebo device and placebo pill.

The subjects were exposed to the florescent light box as soon as possible after waking for 30 minutes each day. Researchers measured effectiveness of each treatment by changes in participants’ scores on the Montgomery-Asberg Depression Rating Scale.

The authors found that the light therapy alone and the combination therapy were effective in treating depression symptoms. About 60 percent of study participants who were in the combined medication with light therapy group reported they were feeling almost normal with the treatments. Participants generally did not suffer any adverse side effects.  

While they were unable to explain why light therapy was effective, the authors theorize that, as with SAD, disrupted circadian rhythms may be linked to non-seasonal depression. Light also affects the same neurotransmitters in the brain targeted by antidepressant medications.

These results, the researchers believe, provide enough evidence to support recommending light treatment for depression patients. The study was limited in that it did not factor in the participants natural light exposure. Light boxes are widely available in stores and from Internet retailers. Most cost less than $150, making them an affordable treatment. The Mayo Clinic suggests that consumers consult their health care provider about light box options.