The U.S. Food and Drug Administration (FDA) has approved Wellbutrin XL(R) for the prevention of seasonal major depressive episodes in patients with a diagnosis of seasonal affective disorder (SAD), a condition affecting about 6 percent of American adults. Wellbutrin XL is the first and only medication approved to prevent seasonal major depressive episodes.

"Seasonal affective disorder is a serious and often under-diagnosed 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. "The FDA approval of Wellbutrin XL for the prevention of seasonal major depressive episodes in adults diagnosed with SAD is exciting. 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."

A combined analysis of three clinical trials showed that Wellbutrin XL reduces the chance of developing a seasonal major depressive episode by 44 percent.

About Seasonal Affective Disorder

Seasonal affective disorder, also known as major depressive disorder with a seasonal pattern, is typically characterized by recurring fall or winter onset of depressive symptoms, with symptoms subsiding during the spring and summer months. While the exact cause is 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.

"Not surprisingly, the prevalence of SAD is highest in the northern parts of the United States where winter daylight hours are shorter and people tend to have less exposure to sunlight," said Rosenthal, who is widely recognized as the first psychiatrist to investigate SAD, as well as the author of numerous articles and a popular book on the topic.

Symptoms of SAD may include depressed mood, overeating (with carbohydrate cravings), weight gain, lethargy and increased sleep.

About the Studies

Although antidepressant medications have been used to treat acute seasonal major depressive episodes in patients with SAD, these studies with Wellbutrin XL were among the first pharmacologic studies to explore the possibility of preventing the onset of autumn-winter depression by starting treatment with an antidepressant early in the season, prior to experiencing symptoms.

Two placebo-controlled clinical trials were conducted during the 2002-2003 autumn-winter seasons and a third trial during the 2003-2004 autumn-winter season. A total of 1,042 outpatients were enrolled in the autumn, prior to experiencing symptoms. The Seasonal Pattern Assessment Questionnaire (SPAQ) was administered at screening to evaluate the historical pattern and severity of seasonal depressive symptoms. Subjects received matching placebo or Wellbutrin XL: the dosing started at 150 mg/day for the first week, with an increase up to 300 mg/day. Treatment was discontinued in the early spring. Primary efficacy endpoints were depression-free rates at end-of-treatment and time-to-onset for recurrence of a seasonal major depressive episode.

In the three studies, patients who enrolled suffered an average of 13 previous seasonal major depressive episodes. Nonetheless, despite this chronic pattern, only 41 percent of subjects reported that they had previously been treated for this condition -- 23 percent with light therapy and 76 percent with antidepressants. More than half of the subjects reported that their seasonal symptoms constituted a marked or severe problem for them. A substantial proportion (61 percent) of subjects reported weight changes across the seasons (greater than or equal to 8 lbs.) -- primarily in the autumn and winter months.

The results of these three placebo-controlled efficacy studies provide evidence that Wellbutrin XL is effective in the prevention of seasonal major depressive episodes in patients with a diagnosis of SAD. The efficacy for the prevention of a seasonal major depressive episode is demonstrated by the depression-free rates in patients treated with Wellbutrin XL compared to those treated with placebo. For all three studies combined, the depression-free rate at the end-of-treatment was higher in the Wellbutrin XL group than the placebo group (84.3 percent vs. 72 percent), showing a treatment difference of 12.3 percent. The time-to-onset of a seasonal major depressive episode favored the Wellbutrin XL group over placebo across the three studies, and was statistically significant in the study conducted during the 2003-2004 autumn- winter season (p<0.001). Observed results were consistent across the two seasons over which the three studies were conducted.

In these studies, the tolerability of Wellbutrin XL was consistent with that seen in previous trials for major depressive disorder. Common adverse events were dry mouth, nausea, constipation and flatulence occurring in greater than or equal to 5 percent of subjects and at a rate exceeding 1.5 times that of placebo.


Wellbutrin XL is not for everyone. There is a risk of seizure with Wellbutrin XL, which 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 inhibitors (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.

Wellbutrin XL is approved only for adults 18 years and over. In some children and teens, antidepressants increase suicidal thoughts or actions. Whether or not a person is taking antidepressants, they or their family should call the doctor right away if they have worsening depression, thoughts of suicide, or sudden or severe changes in mood or behavior, especially at the beginning of treatment or after a change in dose (see Medication Guide: What is important information I should know and share with my family about taking antidepressants? available at


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