More about Seasonal Affective Disorder

Unless you're an avid skier or snowboarder, you probably don't relish the onset of a long winter. For certain people who live in northern climates, the cold, dark days of winter make them feel so sluggish and withdrawn it's hard to get out of bed and maintain daily life.

People who start feeling depressed in the fall or winter, but experience relief from their symptoms with the buds of spring, may have seasonal affective disorder, also called SAD. For men and women who are diagnosed with this condition, light therapy, or other treatments, can restore their energy and alleviate their depression. Below, Michael Terman, PhD, a professor of clinical psychology at the Columbia University College of Physicians and Surgeons and president of the Center for Environmental Therapeutics, discusses how to identify and cope with seasonal depression.

Seasonal affective disorder (SAD) is characterized by symptoms that start in the fall and snowball in the winter months, and then spontaneously disappear come springtime. It usually starts off with feelings of fatigue, difficulty getting up in the morning, a big afternoon slump, and then a taste for carbohydrate-rich foods. Coupled with that fatigue, and you have a formula for weight gain. And so there's often significant weight gain in SAD.

As the symptoms increase, we begin to see depression. The mood goes down, there's a loss of interest in things that normally motivate people. It's difficult to concentrate and get through the day to initiate and complete projects. There's a withdrawal from social contact, including a depressed sex drive, which would be unusual for the same person in the spring or the summer.

One of the classic symptoms of seasonal affective disorder is what we call hypersomnia, where you sleep significantly longer than you sleep in the summer. Hypersomnia is different from person to person, for example if you're a six-hour sleeper in the summer, and you start sleeping eight hours in the winter, you are relatively hypersomnic. But some people will start to sleep 12,13 or 14 hours a day.

SAD exists in degrees of severity. Full-blown SAD means literally that you have a clinically severe major depressive episode during the winter. But many people show the same cluster of physical symptoms and feel only mildly depressed during the winter, and we call that sub-SAD.

SAD is widely prevalent throughout the population, and it's worse the farther north you go. In the middle tier of the United States, up to Southern Canada, it's far more prevalent than in the South of the United States. And most of the people who have SAD have depression in their family.