Seasonal affective disorder (depression)

Head | Psychiatry | Seasonal affective disorder (depression) (Disease)


Seasonal affective disorder (SAD) is a form of recurrent depressive or bipolar disorder, with episodes that vary in severity. Seasonal patterns of depressive episodes are common, but SAD seems to be less common than such patterns suggest. SAD was at first believed to be related to abnormal melatonin metabolism, but later findings did not support this hypothesis. Studies of brain serotonin function support the hypothesis of disturbed activity. The short-allele polymorphism for serotonin transporter is more common in patients with SAD than in healthy people. Atypical depressive symptoms commonly precede impaired functioning, and somatic symptoms are frequently the presenting complaint at visits to family physicians.

Causes and Risk factors

The specific cause of seasonal affective disorder remains unknown. Its likely, as with many mental health conditions, that genetics, age and, perhaps most importantly, the bodys natural chemical makeup all play a role in developing the condition.

Diagnosis and Treatment

The best treatment regimens include 2500 lx of artificial light exposure in the morning. When patients seem to have no response or to prefer another treatment, antidepressants should be considered. Patients with seasonal affective disorder have episodes of major depression that tend to recur during specific times of the year, usually in winter. Like major depression, seasonal affective disorder probably is underdiagnosed in primary care settings.

Although several screening instruments are available, such screening is unlikely to lead to improved outcomes without personalized and detailed attention to individual symptoms. Physicians should be aware of comorbid factors that could signal a need for further assessment. Specifically, some emerging evidence suggests that seasonal affective disorder may be associated with alcoholism and attention-deficit/hyperactivity disorder. ...