Light Therapy Effectively Treats Non-Seasonal Depression

Doctors have known for some time that treatment with high-intensity light (7,000–10,000 Lux) can improve seasonal depression. In an 8-week study published in the journal JAMA Psychiatry in 2015, researcher Raymond Lam compared four different treatment options for non-seasonal major unipolar depression: bright light therapy for 30 minutes per day first thing in the morning, 20 mg of the antidepressant fluoxetine per day, combined bright light therapy and fluoxetine, and a placebo device paired with a placebo pill.

The combination of bright light therapy and fluoxetine produced remission in 58.6% of the participants who received it, compared to remission rates of 43.8% for bright light alone, 19.4% for fluoxetine alone, and 30% for placebo. It is notable that the effects of fluoxetine did not exceed those of placebo, but the effects of light alone did. There were few side effects in any group.

These data provide convincing evidence of the efficacy of light therapy in the treatment of non-seasonal unipolar depression. Use of light therapy for non-seasonal depression should now be more routinely considered, particularly when combined with antidepressant treatment.

Patients who had previously failed to respond to two or more antidepressants and patients with bipolar depression were excluded from the study. Bright light therapy administered in the morning can sometimes bring about mixed states in people with bipolar disorder. A 2007 case study by D. Sit and colleagues in the journal Bipolar Disorders found that midday light led to more improvement and less risk of mixed states than morning light among women with bipolar disorder.

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