Seasonal Affective Disorder: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 4/12/2019

Seasonal affective disorder (SAD) is a form of depression that tends to occur with the shortening of daylight hours during the fall and winter months, but some people may experience it during the summer.

Signs and symptoms associated with seasonal affective disorder are similar to those of other forms of depression. These include sadness, crying spells, feelings of hopelessness and discontent, trouble concentrating, sleep disturbances, tiredness, and fatigue. Other symptoms can include a loss of sex drive, decreases in activity, changes in eating habits, anxiety, and irritability. In severe cases there may be thoughts of suicide or self-harm.

Cause of seasonal affective disorder

Although the cause seasonal affective disorder is not fully understood, medical professionals believe it arises from inadequate exposure to bright light during the winter months.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

Medically Reviewed by a Doctor on 4/12/2019

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