Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: https://medlineplus.gov/seasonalaffectivedisorder.html

Seasonal Affective Disorder

Also called: SAD, Seasonal depression, Seasonal mood disorder

Summary

Seasonal affective disorder (SAD) is a type of depression that comes and goes with the seasons. It usually starts in the late fall and early winter and goes away during the spring and summer. Some people do have episodes of depression that start in the spring or summer, but that is a lot less common. Symptoms of SAD may include:

  • Sadness
  • Gloomy outlook
  • Feeling hopeless, worthless, and irritable
  • Loss of interest or pleasure in activities you used to enjoy
  • Low energy
  • Difficulty sleeping or oversleeping
  • Carbohydrate cravings and weight gain
  • Thoughts of death or suicide

SAD is more common in women, young people, and those who live far from the equator. You are also more likely to have SAD if you or your family members have depression.

The exact causes of SAD are unknown. Researchers have found that people with SAD may have an imbalance of serotonin, a brain chemical that affects your mood. Their bodies also make too much melatonin, a hormone that regulates sleep, and not enough vitamin D.

The main treatment for SAD is light therapy. The idea behind light therapy is to replace the sunshine that you miss during the fall and winter months. You sit in front of a light therapy box every morning to get daily exposure to bright, artificial light. But some people with SAD do not respond to light therapy alone. Antidepressant medicines and talk therapy can reduce SAD symptoms, either alone or combined with light therapy.

NIH: National Institute of Mental Health

Learn More

Genetics

Clinical Trials

Patient Handouts

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.