Seasonal affective disorder is a form of depression thought to be triggered by a decrease in exposure to sunlight. Besides depressed mood and general symptoms of depression, symptoms may include:

 
• Cravings for sweet and starchy foods  
• Weight gain  
• A need for more sleep

This type of depression may be less severe than major depression. The condition usually disappears in the spring.

Seasonal Affective Disorder (SAD)

Definition

A form of depression that recurs with a fall-winter onset and a spring-summer remission (also known as SAD).
Causes, incidence, and risk factors

The cause of seasonal affective disorder (SAD) is not known, but is thought to be related to the body’s temperature and hormone regulation. The disorder is rare, and most people with the “winter blahs” or cabin fever do not have SAD. The disorder may have its onset in adolescence or early adulthood, and it occurs more frequently in women than in men.

Symptoms

 
• depression with a fall or winter onset  
• lack of energy  
• decreased interest in work or significant activities  
• increased appetite with weight gain  
• carbohydrate cravings  
• increased sleep, excessive daytime sleepiness  
• social withdrawal  
• afternoon slumps with decreased energy and concentration  
• slow, sluggish, lethargic movement

Signs and tests

A psychological evaluation rules out other causes for the symptoms and confirms the diagnosis.

Treatment
Light therapy for varying periods of time under special bright light seems to make the symptoms subside. However, the symptoms usually reappear when the therapy is discontinued. Full-spectrum fluorescent light is being investigated as a treatment.

Expectations (prognosis)
The outcome is expected to be good with continuous treatment. Some people may be affected with this disorder throughout their lives.
Complications

The disorder can sometimes progress to a full major depressive syndrome, but spontaneous remission (especially with the change of seasons) is common.

Calling your health care provider
Call for an appointment with your health care provider if you experience symptoms of seasonal affective disorder and it is affecting your lifestyle or work.

Prevention
Unknown