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Seasonal Affective Disorder

Medically reviewed by Last updated on May 6, 2024.

What is seasonal affective disorder (SAD)?

SAD is a type of depression that happens during a change of seasons. SAD usually happens during autumn and winter months when there is less sunlight because the days are shorter. This is called winter-onset depression. Symptoms usually go away in late spring or early summer. Episodes of SAD may be mild or severe.

What causes SAD?

The cause of SAD is not known. You may produce more of a brain chemical called melatonin that regulates sleep. Melatonin levels should increase in the evening and decrease in the morning. You may also produce less of a chemical called serotonin that causes a happy mood.

What increases my risk for SAD?

What other signs or symptoms may I have?

How is SAD diagnosed?

Your healthcare provider will ask if you feel depressed during certain times of the year. Your provider will ask if symptoms go away when the season changes and if you had the same symptoms the year before. You have to have the same symptoms at least 2 years in a row for your provider to diagnose SAD. Tell your provider if you have depression any other time of the year. This may mean you have a different kind of depression than SAD.

How is SAD treated?

Your healthcare provider may recommend a combination of the following:

Treatment options

The following list of medications are related to or used in the treatment of this condition.

What can I do to prevent or manage SAD?

Call your local emergency number (911 in the US) if:

When should I call my doctor?

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.