Symptoms and Signs of Seasonal Affective Disorder (SAD)

Medical Author:
Medically Reviewed on 7/29/2021

Doctor's Notes on Seasonal Depression (Seasonal Affective Disorder, SAD)

Seasonal affective disorder (SAD, seasonal depression) is a type of depression linked to the seasons of the year. The majority of people who have SAD have symptoms mainly in the late fall and winter seasons (a few have summer SAD), and SAD is most common in young adult women. Signs and symptoms may include depressed mood, fatigue, loss of interest in activities, feelings of worthlessness or hopelessness, poor concentration, indecisive and thoughts of death or suicide. These occur at about the same time each year for the individual. Some experience anxiety in anticipation of the seasonal changes and their returning symptoms. People with winter SAD may also exhibit excess sleeping, craving for sugar, starchy foods or alcohol, weight gain, heaviness in arms and legs, have social conflicts, and behavioral changes. Other signs and symptoms of summer SAD include insomnia, poor appetite, weight loss, agitation, and anxiety.

The exact causes of SAD are unknown. However, SAD may run in families and may be related to alcohol abuse, and low levels of vitamin D. Some researchers believe chemical changes occur in the brain when sunlight is reduced or increased as seasons change.

What Are the Treatments for Seasonal Depression (Seasonal Affective Disorder, SAD)?

Antidepressants treat SAD. However, bupropion is the only medication FDA-approved for prevention of major depression diagnosed with SAD. Other treatments include the following:

  • Cognitive behavioral therapy
  • Phototherapy (light therapy)
  • Talk therapy (modifying behaviors, stress reduction)
  • Chronotherapy (resetting sleep schedule)

Your doctor will recommend a treatment plan that is best for your symptoms.


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