The FDA yesterday approved GlaxoSmithKline’s Wellbutrin XL (bupropion HCL extended release tablets) for prevention of major depressive episodes in patients with a history of seasonal affective disorder (SAD). The approval is the first for the treatment of the condition.  Wellbutrin XL previously was approved for treatment of major depressive disorder.SAD afflicts about 6 percent of adult Americans, many of them women, during the fall and winter, according to a study last year for the National Institutes of Health. Seasonal affective disorder is typically mild, but it can also be quite severe, with symptoms similar to those experienced by sufferers of major depression, such as lack of sleep, loss of appetite and suicidal thinking. These episodes can last as long as six months and impair an individual’s ability to socialize, have a relationship and work. “Seasonal affective disorder can significantly impair the quality of life of patients with this condition,” Dr. Steven Galson, director of the FDA’s drug review office, said in a statement. “Today’s approval can help patients with this condition avoid the depressive symptoms and impaired functioning that typically affect them in the fall and winter.” Tests of 1,042 patients with a history of severe seasonal affective disorder found that use of Wellbutrin XL worked. At the end of treatment, 84 percent of patients on the drug were depression-free, compared with 72 percent on the placebo.