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What is Seasonal Affective Disorder?

What is Seasonal Affective Disorder?

This material has been reviewed for accuracy by: Renee Albers, PhD

View of an empty street through a rainy window indicating the feelings of Seasonal Affective DisorderYou might have heard the term Seasonal Affective Disorder, or SAD, used to describe that down-in-the-dumps feeling when winter sets in.

Cold weather, gray skies and short daylight hours can sometimes bring on feelings of sadness, lethargy or despair – especially during the holiday season, when it seems everyone around us is in a joyous mood. With symptoms that can last up to four to five months during the year, SAD is a type of clinical depression recognized by mental health professionals. It’s classified as “major depressive disorder with seasonal pattern,” according to the American Psychiatric Association (APA). There are known symptoms and treatments specific to SAD.


About 5% of the U.S. population is affected by SAD in any given year, according to both the American Psychiatric Association and Mental Health America, a nonprofit mental health advocacy organization. The National Institute of Mental Health (NIMH) website says the condition is much more common in women than in men.Button with GeneSight logo and text learn more about the GeneSight test

SAD is more common in people who have been diagnosed with major depressive disorder or bipolar disorder. While onset of the condition can occur at any age, it’s more likely to begin between the ages of 18 and 30, according to the APA website.

Geographic Variability

As a general rule, people living farther from the equator are more likely to be affected by SAD, as areas of higher latitude have shorter daylight hours during the winter, according to the NIMH website. Previous U.S. community surveys have shown 9.7% of residents in areas of New Hampshire had SAD, compared to 1.4% in of residents in areas of Florida, according to an article published in the Psychiatry Research Journal.


The NIMH website lists the following symptoms, often associated with major depression, noting that not everyone with SAD experiences all symptoms:

Young woman in snow gear stitting on a swing in a snowy playground representing how winter can impact Seasonal Affective Disorder

  • “Feeling depressed most of the day, and nearly every day
  • Losing interest in activities you once enjoyed
  • Experiencing changes in appetite or weight
  • Having problems with sleep
  • Feeling sluggish or agitated
  • Having low energy
  • Feeling hopeless or worthless
  • Having difficulty concentrating
  • Having frequent thoughts of death or suicide”

There are other symptoms that are more likely to occur in winter, such as hypersomnia (oversleeping), overeating (especially carbohydrates), weight gain and social withdrawal.

Light therapy box used in treatment of Seasonal Affective Disorder

Treatment Options

If you think you might be affected by SAD, talk to your healthcare provider or a mental health professional. Multiple treatment options are available for people suffering from SAD. According to the NIMH, these include:

  • Light therapy, or increased exposure to light. One of the most frequently prescribed treatments is the use of a light box that simulates sunlight.
  • Psychotherapy, such as cognitive behavioral therapy, a form of talk therapy that helps patients cope with difficulty
  • Antidepressant medications such as selective serotonin reuptake inhibitors
  • Vitamin D. While Vitamin D supplements might help, studies are inconclusive.

Treatments are often specific to an individual, so talk to your healthcare provider about what might work for you.

For additional details on this condition, please see the following articles:

Seasonal Affective Disorder (SAD) Has These Known Symptoms

What is Seasonal Affective Disorder?

Tips to Cope with Seasonal Affective Disorder (SAD)

Our articles are for informational purposes only and are reviewed by our Medical Information team, which includes PharmDs, MDs, and PhDs. Do not make any changes to your current medications or dosing without consulting your healthcare provider.

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