The news that bipolar depression light therapy may be effective is good news and follows a series of studies this past year highlighting the importance of treatments that affect circadian rhythms by manipulating light and dark in treating mood disorders.
Bipolar depression is one of the hardest conditions to treat effectively. Antidepressant medications may have significant side effects, including inducing mania, and often are not helpful.
People with bipolar depression often experience sleep problems and lethargy and show other signs suggesting that their circadian rhythms may be disrupted and they may benefit from treatments that enhance those rhythms.
The study was a double-blind, placebo controlled study (using a sham red placebo light therapy) of 46 adults with bipolar I or II disorder who had symptoms of major depression Participants were randomly assigned to either a 7,000-lux bright white light or 50-lux dim red placebo light unit, which they agreed to use daily at home or work. All patients started with a 15-minute light session between noon and 2:30 p.m. that increased by 15 minutes each week to a target dose of 60 minutes daily.
Kit and colleagues chose midday light since it tends to have a subtler effect on circadian rhythms, allowing for better mood with less risk of sleep problems or triggering hypomania. They also employed the gradual increase in duration and maintained patients on antimanic medication to further reduce the risks of emerging mania.
A noticeable effect of bright light therapy was observed by four weeks, which is on par with previous studies testing light therapy for seasonal or non-seasonal depression. No hypomania or dramatic mood switching was observed during the study.
The bipolar depression light therapy group had a significantly higher remission rate. In the bright light group 68.2% had full remission of depression at six weeks compared with 22.2% in the placebo group.
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Other ways of strengthening circadian rhythms
References
American Journal of Psychiatry 0 0:0