美国国家公共电台 NPR Light Therapy Might Help People With Bipolar Depression（在线收听）

RACHEL MARTIN, HOST:

We try not to obsess about this too much, but we really do get to work very early around here. We don't get a whole lot of sunlight, especially in the winter months. So when you look around the newsroom, you see these special lamps on some of our colleagues' desks. And people say that light therapy really does work. Research has shown that it can help with depression. And as NPR's Patti Neighmond reports, there's some new evidence that light might even be able to help people with bipolar disorder.

PATTI NEIGHMOND, BYLINE: Some people call it a happy box. It's actually more like a computer monitor. You sit in front of it for an hour a day, and it helps cure the winter blues. It's safe, effective and relatively inexpensive. So researchers at Northwestern University wanted to know if it would work for people with bipolar disorder, too. Psychiatrist Dorothy Sit headed the study.

DOROTHY SIT: We usually ask people to sit in front of the box, a distance of 12 or 13 inches away, and to position the light at eye level.

NEIGHMOND: It shines a bright light that mimics a sunny day outside. Patients don't stare at the light. They just have to sit in front of it.

SIT: They can certainly read - read the paper, journal, look at their bills.

NEIGHMOND: Now, a word of caution - the study was small - 46 patients. Half got the bright white light and half got a placebo that delivered a dim red light. After four to six weeks, Sit says the findings were impressive.

SIT: Sixty-eight percent of the patients improved with bright light therapy versus only 22 percent of patients on the placebo box. So patients returned to work. They are able to look after things at home. They were functioning back to their normal selves again.

NEIGHMOND: Sit wants to see her findings duplicated in more studies. And she says future research should measure internal body clocks to see whether slumps or upswings in energy effect bipolar depression and whether other brain changes occur. And there's an important caveat for people with bipolar disorder.

AL LEWY: The new study is intriguing but highly preliminary.

NEIGHMOND: Psychiatrist Al Lewy with Oregon Health and Science University says patients with bipolar disorder need to consult with their doctor before trying light therapy. This is mostly because the timing of the therapy can make a big difference, especially for people with bipolar disorder who experience intense highs and lows.

LEWY: If you do the light, particularly in the morning, with bipolar depression, you might cause the person to switch into a manic episode.

NEIGHMOND: Which is why patients in the study got their light therapy in the middle of the day. The cycle of highs and lows make bipolar depression much more difficult to treat than other types of depression. Psychiatrist Ken Duckworth, medical director of the National Alliance on Mental Illness, says that's because medications like mood stabilizers and antidepressants work well to treat the manic phase of the disorder but not the depressive phase.

KEN DUCKWORTH: People with bipolar disorder spend most of their time on the depressive end of the spectrum. And this difficulty is compounded by the fact that we don't have very good treatments for the depressive phase of bipolar disorder.

NEIGHMOND: So while there's a lot more research to be done, Duckworth says light therapy could be a promising, non-drug treatment for patients with bipolar depression. Patti Neighmond, NPR News.