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Seasonal Affective Disorder

Seasonal affective disorder (SAD), also referred to as seasonal depression, is a form of depression that is dependent on the time of year. It typically starts in the fall or winter and disappears during the spring or by the beginning of summer. A unique type of SAD called summer depression starts in late spring or early summer and concludes by fall.

Causes of Seasonal Affective Disorder

The precise cause of SAD is unknown, but it is highly influenced by location in terms of latitude and the degree of sunlight in that region. One school of thought holds that when a person is exposed to less sunlight (such as in the wintertime), the biological clock that controls mood, sleep, and hormones is retarded. Contact with light may reset the biological clock to its normal state.

Another point of view is that neurotransmitters (the chemicals that exchange information among the nerves of the brain) may be out of sync in people with SAD. Some experts think that being out in the sun will fix this imbalance.

Seasonal Affective Disorder Symptoms

People affected by SAD exhibit a variety of common signs of depression such as unhappiness, anxiety, irritability, lack of interest in enjoyable activities, avoidance of social events, and lack of focus. Symptoms typically include exhaustion, weakness, increased time spent sleeping, increased appetite (e.g., greater consumption of carbohydrates), and weight gain.

Symptoms of winter SAD include:

• Tiredness
• Craving for more sleep
• Less energy
• Weight gain
• Greater food intake
• Inability to concentrate
• Increased introversion

Symptoms of summer SAD include:

• Weight loss
• Insomnia
• Loss of appetite