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ILLUSTRATION: ISTOCK. FOR STOCKISTS, SEE PAGE 125
Seasonal Affective Disorder (SAD) is depression that typically follows a seasonal pattern. In the most common form, SAD recurs in late autumn or early winter and persists until the following spring or summer. No one knows exactly what causes SAD, but it is likely a response to shorter hours of daylight. SAD is rare close to the equator, but more prevalent at higher latitudes. Adults under the age of 30 and women are at highest risk. Symptoms include low moods, fatigue, social withdrawal, a craving for carbohydrate foods and weight gain. There are no medical tests specific to SAD – it is diagnosed on the basis of a careful history and examination so that physical causes can be excluded with confidence. Symptoms similar to those associated with SAD may occur in medical conditions, such as acute viral infection or an underactive thyroid, so if you believe you have SAD, consult your physician.