A sunny day on February 2 is bad news for most of us —if official groundhog Punxsutawney Phil sees his shadow, there will be six more weeks of winter. But sunshine is just what the doctor ordered for sufferers of SAD (Seasonal Affective Disorder).

SAD is a depressive mood disorder very similar to bipolar disorder, with one key difference, says Anantha Shekhar, Raymond E. Houk Professor of Psychiatry at the Indiana University School of Medicine. Unlike bipolar disorder (also known as manic depressiveness), SAD is somehow triggered by lack of light.

Starting in September, as the days grow shorter, SAD begins to kick in, Shekhar explains. By the winter equinox in December, the disorder is typically peaking. Although January and February can often be terrible winter months, daylight begins to lengthen then, and the impact of SAD usually starts to recede. As February creeps toward spring, your winter blues may be peaking, but true sufferers of SAD are probably feeling better.

People with full-blown SAD experience symptoms of classic depression—including disturbances in sleep and appetite, fatigue, and feelings of hopelessness—on a seasonal cycle. According to Shekhar, a SAD diagnosis is not made unless a person has recurrent periods of depression in the fall and early winter for at least two to three years. Beyond being triggered by lack of light, the disorder also tends to be genetic, he says.

The severity of SAD differs. For patients with milder cases, light therapy “can often be quite helpful,” Shekhar says. As little as 30 minutes of exposure to light-boxes emitting a very intense, bright light may result in more energy and fewer winter blahs. For patients with severe cases, antidepressant medications are prescribed.

In all cases, Shekhar suggests, counseling can help patients prepare for the SAD months before the days grow gray and gloomy.

And a long vacation in Florida wouldn't hurt, either.

To listen to an interview with Shekhar about SAD, go to the Web site for Indiana University's health issues radio show, Sound Medicine: http://soundmedicine.iu.edu/archive/2002/122102.html#segment_1

To read a recent Q&A with Shekhar on SAD in The Indianapolis Star , click here: www.indystar.com/apps/pbcs.dll/article?AID=/20051227/LIVING01/512270333/1083

For a SAD fact sheet, see the National Mental Health Association:
www.nmha.org/infoctr/factsheets/27.cfm