More than 13 million American adults suffer from the "winter blues."

When Terri Bloom moved to Buffalo, N.Y., 20 years ago, she noticed a shift in her mood during the first winter. As the days got shorter and darker, Bloom became depressed. Figuring it was simply related to the stress from the move and the new distance from her friends and family, she shrugged it off, ultimately feeling better when the spring came. It was only after the depression returned the next winter that she went to her doctor, who identified what Bloom was experiencing as seasonal affective disorder, or SAD.

"When I was first diagnosed with SAD, we noticed my sleep pattern was especially affected," Bloom said. "Some days I couldn't sleep at all; other days, I'd sleep for 12 hours at a time. Generally, I was way down."

In addition, Bloom noticed an effect on her appetite. "I tended to gain weight real easily in the winter," she said. "I would almost forage for chocolate and cookies, and things I don't normally eat."

SAD also took its toll on Bloom's family as she was very withdrawn and felt she just wasn't there for her kids.

"Seasonal affective disorder is a serious and often underdiagnosed form of depression that affects millions of people each year in the United States," said Norman E. Rosenthal, M.D., clinical professor of psychiatry at Georgetown Medical School and medical director of Capital Clinical Research Associates.

SAD is typically characterized by depressive symptoms occurring in the fall or winter and then subsiding during the spring and summer months. While the exact cause of the condition remains unknown, SAD is believed to be related to seasonal variations of light, as well as changes in certain brain chemicals, which may induce feelings of depression.

"People with SAD slow down, have difficulty waking in the morning, overeat, oversleep, gain weight, have a hard time concentrating and interacting with friends and family. And can become quite depressed," Dr. Rosenthal said.

Now, the Food and Drug Administration (FDA) has approved Wellbutrin XL? (bupropion hydrochloride extended-release tablets) for the prevention of seasonal major depressive episodes in patients diagnosed with seasonal affective disorder. Wellbutrin XL is the first and only medication approved to prevent these predictable seasonal major depressive episodes.

"The FDA approval of Wellbutrin XL for the prevention of seasonal major depressive episodes in adults diagnosed with SAD is exciting," Dr. Rosenthal said. "For the first time, it may be possible to prevent the predictable onset of SAD with medication by beginning treatment in the autumn season, prior to experiencing depressive symptoms."

Important Safety Information

Wellbutrin XL is not for everyone. There is a risk of seizure with Wellbutrin XL that increases with higher doses. Taking more than 450 mg/day increases the chance of serious side effects. People should not use it if they've had a seizure or eating disorder, or if they abruptly stop using alcohol or sedatives. People should not take Wellbutrin XL with monoamine oxidase inihibitors (MAOIs), or medicines that contain bupropion. When used with a nicotine patch or alone, there is a risk of increased blood pressure, sometimes severe. To reduce risk of serious side effects, people should tell their doctor if they have liver or kidney problems. Other side effects may include flatulence, constipation, weight loss, dry mouth, nausea, difficulty sleeping, dizziness or sore throat.