Covers causes and symptoms of seasonal affective disorder (SAD), also known as winter depression. Includes info on bright light therapy and dawn simulation treatment. Discusses the use of melatonin, antidepressants, and counseling.
Seasonal Affective Disorder (SAD)
What is seasonal affective disorder (SAD)?
Seasonal affective disorder, or SAD, is a type of
depression that occurs during the same
season each year. You may have SAD if you felt depressed during the last two winters but felt much better in
spring and summer.
Anyone can get SAD, but it's more common in:
People who live far from the equator, where winter daylight hours
are very short.
People between the ages of 15 and 55.
The risk of getting SAD for the first time goes down as you age.
People who have a close relative with SAD.
SAD is sometimes called winter depression or seasonal depression.
What causes SAD?
Experts aren't sure what causes
SAD. But they think it may be caused by a lack of sunlight. Lack of light may:
Upset your "biological clock," which controls your sleep-wake pattern and other circadian rhythms.
Symptoms come and go at about the same time each year.
Most people with SAD start to have symptoms in September or October and feel better by
April or May.
How is SAD diagnosed?
It can sometimes be hard to
tell the difference between SAD and other types of depression because many of the
symptoms are the same. To diagnose SAD, your doctor will ask
You have been depressed during the same
season and have gotten better when the seasons changed for at least 2 years in
You have symptoms that often occur with SAD, such as being
very hungry (especially craving carbohydrates), gaining weight, and sleeping
more than usual.
A close relative—a parent, brother, or sister—has
You may need to have blood tests to rule out other conditions that can cause similar symptoms, such as low thyroid (hypothyroidism).
Your doctor may also do a mental health assessment to get a better idea of how you feel and how well you are able to think, reason, and remember.
How is it treated?
Light therapy is the main treatment for SAD. Medicines and counseling may also help.
Experts think light therapy works by resetting your biological clock. It helps most people who have SAD, and it's easy to use.
There are two types of light therapy:
Bright light treatment. For this treatment,
you place the light box at a certain distance from you on a desk or table. Then you sit in front of it while you read, eat breakfast, or work at a computer.
Dawn simulation. For this treatment, a dim light goes on
in the morning while you sleep, and it gets brighter over time, like a sunrise.
Light boxes use fluorescent lights that are brighter than indoor lights but not as bright as sunlight. Ultraviolet lights, full-spectrum lights, tanning lamps, and heat lamps should not be used.
Light therapy is usually prescribed for 30 minutes to 2 hours a day. The amount of time depends on how strong the light is and on whether you are starting out or are have been using it for a while.
You may start to feel better within a week or so after you
start light therapy. But you need to stay with it and use it every day until
the season changes. If you don't, your depression could come back.
Antidepressant medicines may help people who have SAD. They may be used alone or with light therapy. The most common ones prescribed for SAD include:
Selective serotonin reuptake inhibitors (SSRIs), such as paroxetine (Paxil) and sertraline (Zoloft). SSRIs are usually tried first.
Other antidepressants, such as bupropion (Wellbutrin) and venlafaxine (Effexor).
If your doctor prescribes an antidepressant, be sure you
take it the way you're told to. Do not stop taking it suddenly. This could cause side effects or make your depression worse. When
you are ready to stop, your doctor can help you slowly reduce the dose to
Regular exercise is one of the best things you can do for yourself.
Getting more sunlight may help too, so try to get outside to exercise when the sun is shining. Being active during the daytime, especially early in the day, may
help you have more energy and feel less depressed.
Moderate exercise such as walking, riding a stationary
bike, or swimming is a great way to get started. But any activities that raise your heart rate—including daily chores—can help, especially if you can do them outdoors or near a sunny window.
Moderate exercise is safe for most people. But it's always a good idea to talk to your doctor before you start an exercise program.
Some people try complementary treatments to help with SAD.
If you want to use them, be sure to check with your doctor first. They may interact with other medicines or treatments.
St. John's wort is an herb that may help ease depression symptoms.
But you should not take it if you are taking antidepressant medicine. It may make you sensitive to light, so it may not be recommended if you are using light therapy.
Melatonin is a hormone that may help regulate your biological clock. But you need to take a very low dose at a specific time of the day.
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This online resource is provided by the American Psychiatric Association for anyone seeking mental health information. It includes information on many common mental health concerns, including warning signs of mental disorders, treatment options, and preventive measures.
National Alliance on Mental Illness
3803 North Fairfax Drive
Arlington, VA 22203
1-800-950-NAMI (1-800-950-6264) hotline for help with depression (703) 524-7600
The National Alliance on Mental Illness is a national
self-help and family advocacy organization dedicated solely to improving the
lives of people who have severe mental illnesses such as schizophrenia, bipolar
disorder (manic depression), major depression, obsessive-compulsive disorder,
and panic disorder. NAMI focuses on support, education, advocacy, and research.
The mission of the organization is to "eradicate mental illness and improve the
quality of life of those affected by these diseases."
American Psychiatric Association (2010). Practice Guideline for the Treatment of Patients With Major Depressive Disorder, 3rd ed. Available online: http://psychiatryonline.org/guidelines.aspx.
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U.S. Department of Health and Human Services (2008).
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Publication No. U0036). Washington, DC: U.S. Government Printing Office.
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How this information was developed to help you make better health decisions.