Bright white light therapy improves depression in patients with bipolar disorder
Use of midday bright light therapy is effective in patients with bipolar depression, suggests a study.
A 6-week randomized, double-blind, placebo-controlled trial was conducted to assess the efficacy of adjunctive bright light therapy at midday for bipolar depression. Depressed adults with bipolar I or II disorder who were receiving stable dosages of antimanic medication (excluding those with hypomania or mania, mixed symptoms, or rapid cycling) were randomly assigned to either 7,000-lux bright white light or 50-lux dim red placebo light (n=23 for each group).
The investigators used the Structured Interview Guide for the Hamilton Depression Scale With Atypical Depression Supplement (SIGH-ADS), the Mania Rating Scale and the Pittsburgh Sleep Quality Index to assess symptoms weekly. Remission was defined as having SIGH-ADS score of ≤8.
Patients in both treatment groups had moderate depression and no hypomanic or manic symptoms at baseline. Patients treated with bright white light, compared with those in the placebo light group, had a significantly higher remission rate (68.2 percent vs 22.2 percent; adjusted odds ratio, 12.6) at weeks 4‒6 and significantly lower depression scores (9.2 vs 14.9; adjusted β, ‒5.91) at the endpoint visit.
There were no mood polarity switches seen among patients. Both groups had improved sleep quality, which did not show significant difference between them.
“Patients with bipolar disorder have recurrent major depression, residual mood symptoms and limited treatment options,” the investigators said.
In one study, depression during pregnancy was improved significantly more with bright white light treatment for 5 weeks than with placebo dim red light, providing evidence that light therapy, a simple, cost-effective antidepressant modality with minimal side effects for the mother and no known risk for the unborn child, may be a beneficial nonpharmacologic strategy in this situation. [J Clin Psychiatry 2011;72:986-993]