Seasonal affective disorder

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 greater risk for SAD. A less common form of the disorder involves depression during the summer months.

Symptoms

Symptoms usually build up slowly in the late autumn and winter months. Symptoms are usually 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.

The health care provider may also perform a physical exam and blood tests to rule out other disorders that are similar to SAD.

Treatment

As with other types of depression, antidepressant medications and talk therapy can be effective.

MANAGING YOUR DEPRESSION AT HOME

To manage your symptoms at home:

• Get enough sleep.
• Eat a healthy diet.
• Take medicines the right way. Learn 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. Look for activities that make you happy.
• Practice good sleep habits.

Avoid alcohol and illegal drugs. These can make depression worse over time. They may also affect your judgment about suicide.

When you are struggling with depression, talk about how you're feeling to someone you trust. Try to be around people who are caring and positive. Volunteer or get involved in group activities.

LIGHT THERAPY

Light therapy using a special lamp with a very bright light (10,000 lux) that mimics light from the sun may also be helpful.

• Start treatment during the fall or early winter, before the symptoms of SAD begin.
• Follow your health care provider's instructions about how to use light therapy. A common practice is to sit a couple of feet away from the light box for about 30 minutes every day. This is usually done in the early morning, to mimic sunrise.
• Keep your eyes open, but do not look straight into the light source.

Symptoms of depression should improve within 3 - 4 weeks if light therapy is going to help.

Side effects of light therapy include:

• Eye strain and headache
• Mania, less often (see: Bipolar disorder)

People who take drugs that make them more sensitive to light, such as certain psoriasis drugs, antibiotics, or antipsychotics, should avoid light therapy.

A check-up with your eye doctor is recommended before starting treatment.

With no treatment, symptoms usually get better on their own with the change of seasons. However, symptoms can improve more quickly with treatment.

Outlook (Prognosis)

The outcome is usually good with treatment. However, some people have SAD throughout their lives.

When to Contact a Medical Professional

Get help right away if you have thoughts of hurting yourself or anyone else.

References

American Psychiatric Asosciation. Practice guideline for the treatment of patients with major depressive disorder. 3rd ed. October 2010. 

Tesar GE. Psychiatry and psychology. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine 2010. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010:section 11.

Update Date: 2/11/2012

Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; and David B. Merrill, MD, Assistant Clinical Professor of Psychiatry, Department of Psychiatry, Columbia University Medical Center, New York, NY. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Heath Solutions, Ebix, Inc.