Seasonal affective disorder
Seasonal depression; Winter depression; Wintertime blues; SAD
Seasonal affective disorder (SAD) is a type of depression that occurs at a certain time of the year, usually in winter.
Depression is defined as a mood disorder, and there are several subtypes. Bipolar disorder, also known as manic-depressive illness, is considered in a separate category.
Causes
SAD may begin during the teen years or in adulthood. Like other forms of depression, it occurs more often in women than in men.
People who live in places with long winter nights are at high risk of developing SAD. A less common form of the disorder involves depression during the summer months.
If you often feel sad, blue, unhappy, miserable, or down in the dumps, you may have depression. Let's talk about depression, and what you can do to get out of your funk. Depression often runs in families. This may be due to your genes, passed down by your parents and grandparents, the behaviors you learn at home, or both. Even if your genetic makeup makes you more likely to develop depression, a stressful or unhappy life event may triggers the depression. Depression can have many causes, including internal factors like genetics, or negative personality. External factors, substance misuse, or trauma and loss. Common triggers include alcohol or drug use, and medical problems long-term pain, cancer or even sleeping problems. Stressful life events, like getting laid off, abuse at home or on the job, neglect, family problems, death of a loved one, or divorce, can send someone spiraling into depression. There are three main types of depression; major depression, atypical depression and dysthymia. To be diagnosed with major depression, you must demonstrate 5 or more of the primary symptoms for at least two weeks. Atypical depression occurs in about a third of patients with depression, with symptoms including overeating, oversleeping, and feeling like you are weighed down. Dysthymia is a milder form of depression that can last for years if not treated. Other forms include the depression that is part of bipolar disorder, postpartum depression, occurring after a woman gives birth, premenstrual dysphoric disorder, occurring 1 week before a woman's menstrual period and seasonal affective disorder, occurring in both males and females during the fall and winter seasons. No matter what type of depression you have and how severe it is, some self-care steps can help. Get enough sleep if you can, exercise regularly, and follow a healthy, nutritious diet. Avoid alcohol and recreational drugs. Get involved in activities that make you happy and spend time with family and friends. If you are religious, talk to a clergy member. Consider meditation, tai chi, or other relaxation methods. If you are depressed for 2 weeks or longer, contact your doctor or other health professional before your symptoms get worse. Treatment will depend on your symptoms. For mild depression, counseling and self-care may be enough. Either psychotherapy or antidepressant medicines may help, but they are often more effective when combined. Vigorous exercise and light therapy could offer significant benefit alone or in combination. Healthy lifestyle habits can help prevent and treat depression, and reduce the chances of it coming back. Talk therapy and antidepressant medication can also make you less likely to become depressed again. In fact, talk therapy may help you through times of grief, stress, or low mood. In general, staying active, making a difference in the life of others, getting outside and keeping in close contact with other people is important for preventing depression.
Symptoms
Symptoms usually build up slowly in the late autumn and winter months. Symptoms are often the same as with other forms of depression:
- Hopelessness
- Increased appetite with weight gain (weight loss is more common with other forms of depression)
- Increased sleep (too little sleep is more common with other forms of depression)
- Less energy and ability to concentrate
- Loss of interest in work or other activities
- Sluggish movements
- Social withdrawal
- Unhappiness and irritability
SAD can sometimes become long-term depression. Bipolar disorder or thoughts of suicide are also possible.
Exams and Tests
There is no test for SAD. Your health care provider can make a diagnosis by asking about your history of symptoms.
Your provider may also perform a physical exam and blood tests to rule out other disorders that have symptoms similar to SAD.
Treatment
As with other types of depression, antidepressant medicines and talk therapy can be effective.
MANAGING YOUR DEPRESSION AT HOME
To manage your symptoms at home:
- Get enough sleep.
- Eat healthy foods.
- Take medicines the right way. Ask your provider how to manage side effects.
- Learn to watch for early signs that your depression is getting worse. Have a plan if it does get worse.
- Try to exercise more often. Do activities that make you happy.
Do not use alcohol or illegal drugs. These can make depression worse. They can also cause you to think about suicide.
When you are struggling with depression, talk about how you are feeling with someone you trust. Try to be around people who are caring and positive. Volunteer or get involved in group activities.
LIGHT THERAPY
Your provider may prescribe light therapy. Light therapy uses a special lamp with a very bright light that mimics light from the sun:
- Treatment is started in the fall or early winter, before the symptoms of SAD begin.
- Follow your provider's instructions about how to use light therapy. One way that may be recommended is to sit 2 feet (60 centimeters) away from the light box for about 30 minutes each day. This is often done in the early morning, to mimic sunrise.
- Keep your eyes open, but do not look straight into the light source.
If light therapy is going to help, symptoms of depression should improve within 3 to 4 weeks.
Side effects of light therapy include:
- Eye strain or headache
- Mania (rarely)
People who take medicines that make them more sensitive to light, such as certain psoriasis medicines, antibiotics, or antipsychotics, should not use light therapy.
A checkup with your eye doctor is recommended before starting treatment.
With no treatment, symptoms usually get better on their own with the change of seasons. Symptoms can improve more quickly with treatment.
Outlook (Prognosis)
The outcome is usually good with treatment. But some people have SAD throughout their lives.
When to Contact a Medical Professional
If you or someone you know is thinking about suicide, call or text 988 or chat
You can also call 911 or the local emergency number or go to the hospital emergency room. DO NOT delay.
If someone you know has attempted suicide, call 911 or the local emergency number right away. DO NOT leave the person alone, even after you have called for help.
References
American Psychiatric Association website. Depressive disorders. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Text Revision (DSM-5-TR), Washington, DC: American Psychiatric Association Publishing; 2022.
Fava M, Mischoulon D, Cassano P, Papakosta GI, Stern TA. Depressive disorders. In: Stern TA, Wilens TE, Fava M, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 3rd ed. Philadelphia, PA: Elsevier; 2025:chap 28.
Lyness JM, Lee HB. Psychiatric disorders in medical practice. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 362.
National Institute of Mental Health website. Seasonal affective disorder.
Version Info
Last reviewed on: 5/4/2024
Reviewed by: Fred K. Berger, MD, addiction and forensic psychiatrist, Scripps Memorial Hospital, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
