Light therapy uses exposure to bright white artificial light to help treat symptoms of seasonal affective disorder (SAD). This therapy may also benefit people living with bipolar disorder who are suffering from depression, suggest new findings published in the American Journal of Psychiatry, reports NPR.

For the study, researchers at the Feinberg School of Medicine at Northwestern University in Illinois tested light therapy boxes on 46 patients with moderate depression associated with bipolar disorder, a mental health condition that causes extreme mood swings. Scientists administered bright light therapy to half of the participants while the other half were exposed to a dim red placebo light. (Researchers also advised patients to continue taking their regular medication and not to look up information on light therapy or discuss the appearance of their light with other participants.)

Scientists instructed individuals to place the light box at least one foot from their face at midday for a 15-minute session and increased their exposure each week until they received one hour of light every day. (Previous studies showed that early morning therapy could cause people with bipolar disorder to have a manic phase.)

After four to six weeks, findings showed that 68 percent of patients who used bright light therapy reported a remission in depression symptoms compared to 22 percent of patients who received the placebo light. “Effective treatments for bipolar depression are very limited,” said psychiatrist Dorothy Sit, MD, an associate professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and the lead study author. “This gives us a new treatment option for bipolar patients that we know gets us a robust response within four to six weeks.”

Researchers cautioned that patients should not try light therapy on their own, however, because the treatment can trigger hypomania, a less severe form of mania that can ultimately evolve into this period of extremely elevated mood and high energy.

Sit observed that while these findings offer promising results for treating bipolar depression, it’s key that future research duplicate her findings and also show how light affects the body’s circadian rhythms (physical, mental and behavioral changes that follow a daily cycle), such as sleeping at night and being awake during the day, and how that affects bipolar symptoms.

Click here to learn how amber-tinted glasses that block blue light may help treat bipolar disorder.