Light Therapy May Help With the Winter Blues.

For the millions of Americans who suffer from mild to severe winter blues — a condition called seasonal affective disorder, or S.A.D. — bright-light therapy is the treatment of choice, with response rates comparable with those of antidepressants.

Many experts think light therapy is underused, given its affordability and relative lack of side effects.

Patients generally sit in front of the light box, with the bright light emanating from the square surface, in the morning. With the natural dawn being later in winter, the body rhythms drift late. If you can fix the drift, you can fix the depression.

Light therapy may even help with major nonseasonal depression, experts say, and with sleep disorders. And because it has few side effects, researchers are studying whether light therapy can help with depression during pregnancy and be used to treat elderly people with dementia. It is also being investigated for the treatment of bulimia nervosa, severe premenstrual syndrome and even attention deficit hyperactivity disorder and bipolar disorder.

But while part of the appeal of light therapy is that it can be self-prescribed, although experts recommend consulting with a knowledgeable health care provider before starting treatment to rule out other medical conditions and to help with monitoring and adjusting bright-light exposure.