mental health

Seeing the Light: Decreasing Depression in Bipolar Patients

Exposure to bright light at midday significantly decreases symptoms of depression and increased function in individuals with bipolar disorder, according to the results of a recent study.

Previous pilot data has suggested that bright light therapy could help to relieve depressive symptoms in patients with bipolar disorder.

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For their study, the researchers enrolled depressed adults with either bipolar I or II disorder who were receiving stable dosages of antimanic medication. Patients with hypomania or mania, mixed symptoms, or rapid cycling were excluded.

The participants were randomly assigned to either bright light therapy (7000 lux bright white light) or to placebo (50-lux dim red light). The Structured Interview Guide for the Hamilton Depression Scale With Atypical Depression Supplement, Mania Rating Scale, and Pittsburgh Sleep Quality Index were used to assess symptoms on a weekly basis.

Overall, the bright light group saw a significantly higher remission rate (68.2%) compared with the placebo group (22.2%) at weeks 4 through 6 and significantly lower depression scores (9.2 vs 14.9) at endpoint. Sleep quality did not differ between the groups.

“The data from this study provide robust evidence that supports the efficacy of midday bright light therapy for bipolar depression,” the researchers concluded.

—Michael Potts


Sit DK, McGowan J, Wiltrout C, et al. Adjunctive bright light therapy for bipolar depression: a randomized double-blind placebo-controlled trial [published online October 3, 2017]. AJP.