If you notice periods of depression that seem to accompany seasonal changes during the year, you may suffer from seasonal affective disorder (SAD). This condition is characterized by recurrent episodes of depression – usually in late fall and winter – alternating with periods of normal or high mood the rest of the year.
Most people with SAD are women whose illness typically begins in their twenties, although men also report SAD of similar severity and have increasingly sought treatment. SAD can also occur in children and adolescents, in which case the syndrome is first suspected by parents and teachers. Many people with SAD report at least one close relative with a psychiatric condition, most frequently a severe depressive disorder (55 percent) or alcohol abuse (34 percent).
What are the patterns of SAD?
Symptoms of winter SAD usually begin in October or November and subside in March or April. Some patients begin to slump as early as August, while others remain well until January. Regardless of the time of onset, most patients don’t feel fully back to normal until early May. Depressions are usually mild to moderate, but they can be severe. Very few patients with SAD have required hospitalization, and even fewer have been treated with electroconvulsive therapy.
The usual characteristics of recurrent winter depression include oversleeping, daytime fatigue, carbohydrate craving and weight gain, although a patient does not necessarily show these symptoms. Additionally, there are the usual features of depression, especially decreased sexual interest, lethargy, hopelessness, suicidal thoughts, lack of interest in normal activities, and social withdrawal.
Light therapy, described below, is now considered the first-line treatment intervention, and if properly dosed can produce relief within days. Antidepressants may also help, and if necessary can be used in conjunction with light.
In about 1/10th of cases, annual relapse occurs in the summer rather than winter, possibly in response to high heat and humidity. During that period, the depression is more likely to be characterized by insomnia, decreased appetite, weight loss, and agitation or anxiety. Patients with such "reverse SAD" often find relief with summer trips to cooler climates in the north. Generally, normal air conditioning is not sufficient to relieve this depression, and an antidepressant may be needed.