Seasonal depression, often called seasonal affective disorder (SAD), is a depression that occurs each year at the same time, usually starting in fall, worsening in winter, and ending in spring. It is more than just "the winter blues" or "cabin fever." A rare form of SAD, known as "summer depression," begins in late spring or early summer and ends in fall.
What are the symptoms of seasonal affective disorder?
People who suffer from SAD have many of the common signs of depression, including:
- loss of interest in usual activities
- withdrawal from social activities
- inability to concentrate
- extreme fatigue and lack of energy
- a “leaden” sensation in the limbs
- increased need for sleep
- craving for carbohydrates, and accompanying weight gain.
Symptoms of summer SAD include:
- weight loss
- agitation and restlessness
- trouble sleeping
- decreased appetite
How common is SAD?
Approximately one half million of the U.S. population suffers from winter SAD, while 10 to 20 percent may suffer from a more mild form of winter blues. Three-quarters of the sufferers are women, and the onset typically is early adulthood. SAD also can occur in children and adolescents. Older adults are less likely to experience SAD.
This illness is more commonly seen in people who live in cloudy regions or at high latitudes (geographic locations farther north or south of the equator). Individuals who relocate to higher latitudes are more prone to SAD.
What causes seasonal affective disorder?
The exact cause of this condition is not known, but evidence to date strongly suggests that—for those with an inherent vulnerability—SAD is triggered by changes in the availability of sunlight. One theory is that with decreased exposure to sunlight, the internal biological clock that regulates mood, sleep, and hormones is shifted. Exposure to light may reset the biological clock.
Another theory is that brain chemicals that transmit information between nerves, called neurotransmitters (for example, serotonin), may be altered in individuals with SAD. It is believed that exposure to light can correct these imbalances.
How can I tell if I have seasonal affective disorder?
It is very important that you do not diagnose yourself. If you have symptoms of depression, see your doctor for a thorough assessment. Sometimes physical problems can cause depression. But other times, symptoms of SAD are part of a more complex psychiatric problem. A mental health professional typically can evaluate your pattern of symptoms and identify whether you have SAD or another type of mood disorder.
How is seasonal affective disorder treated?
Research now shows that phototherapy, also known as bright light therapy, is an effective treatment for SAD. Sometimes antidepressant medicine is used alone or in combination with light therapy. Spending time outdoors during the day can be helpful, as well as maximizing the amount of sunlight you're exposed to at home and in the office.
What is light therapy? Is it safe?
Light therapy, sometimes called phototherapy, is administered by a device that contains white fluorescent light tubes covered with a plastic screen to block ultraviolet rays. The intensity of light emitted (Lux) should be 10,000 Lux. The patient does not need to look directly into the light, but reads or eats while sitting in front of the device at a distance of 2 to 3 feet.
Light therapy is generally safe and well tolerated. However, there are some contraindications (e.g., conditions such as diabetes or retinopathies, certain medications) because of the potential risk of damage to the retina of the eye. Bright light therapy can cause hypomanic or manic symptoms; therefore, individuals with bipolar affective disorder require medical supervision to use light therapy.
Side effects of light therapy include:
- eye strain
At what time of the day and for how long should I use light therapy?
The timing of light therapy appears to affect the treatment response. Recent studies suggest that morning light therapy is more effective than evening treatments. Using this treatment too late in the day may produce insomnia. Many health professionals today prefer to treat SAD with 10,000 Lux for 15 to 30 minutes every morning. Patients often see improvement within two to four days, and reach full benefits within two weeks. The symptoms of SAD return quickly after light therapy is stopped, so light treatment should be continued throughout the entire season of low sunlight.
Even though they generate enough light, tanning beds should not be used to treat SAD. The amount of ultraviolet (UV) rays they produce is harmful to the skin and eyes.
Can I prevent the onset of seasonal affective disorder?
If you think you have symptoms of SAD, see your doctor for a thorough examination. Your doctor will want to make sure that these symptoms are not caused by another psychiatric condition or major medical illness.
If you have been diagnosed with SAD, here are some things you can do to help prevent it from coming back:
- Begin using a light box at the start of the fall season, even before you feel the onset of winter SAD.
- Try to spend some amount of time outside every day, even when it's very cloudy. The effects of daylight are still beneficial.
- Eat a well-balanced diet and include sufficient amounts of vitamins and minerals as recommended by the FDA. This will help you have more energy even though your body is craving starchy and sweet foods.
- Try exercising for 30 minutes a day, three times a week.
- Stay involved with your social circle and regular activities. This can be a tremendous means of support during winter months.
- Consider consulting a mental health professional trained in cognitive behavior therapy, which has been demonstrated as an effective treatment for SAD.
- Talk to your doctor about antidepressant medication if your symptoms are severe or persist despite interventions such as bright light therapy.
If your symptoms become severe and you or someone you know are having thoughts of suicide, call your doctor right away or go to the nearest emergency room.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 11/12/2013…#9293