Seasonal Affective Disorder

Are You SAD? The AMA Warns of a Common Cold-Weather Malady

The fourth edition of the American Medical Association Family Medical Guide explains how to recognize and treat seasonal affective disorder

Hoboken, NJ -Does your mood drop along with the temperature? If the answer is yes, you may not be imaging it. Many people experience a form of depression that occurs in the fall or winter in response to shorter days with less sunlight. The disorder subsides in the spring or summer as daylight increases. The medical community has a name for this condition: seasonal affective disorder, also known as SAD.

The exact cause of SAD is unclear. The deficiency of light during fall and winter is thought to decrease the level in the brain of the chemical messenger serotonin. Serotonin affects emotions, behavior, and thought. People with SAD may also have altered circadian rhythms, or internal biological clocks, that cause a shift in the signals that indicate when to fall asleep and when to wake up.

If you think you may have seasonal affective disorder, it's a good idea to learn all you can about it. SAD is covered thoroughly in the fourth edition of the American Medical Association Family Medical Guide (Wiley; 2004; ISBN: 0-471-26911-5; Cloth/$45.00). Below are some facts and helpful advice from this indispensable reference book.

The Science Behind SAD

Normally, the light-sensing pineal gland in the brain responds to the lessening light of day by secreting the hormone melatonin, which promotes relaxation and sleep. Daylight signals the pineal gland to shut off the production of melatonin to allow us to wake up. Melatonin levels should be low in the morning and high at bedtime, but melatonin is produced in increased quantities throughout the day in winter, when the days are shorter and darker. Maintaining this cycle becomes more difficult in the fall and winter because the body is no longer responding to stark contrasts in day and night or light and darkness.

The short daylight hours and lack of sunlight during winter can also cause a chemical imbalance in an area of the brain called the hypothalamus, which plays a role in regulating the body's biological clock. Cold weather adds to the chemical imbalances caused by low light levels by encouraging people to spend more time indoors. Some doctors think that SAD may be the human counterpart to the seasonal cycles of animals that influence activities such as hibernation. SAD affects more women than men and is most common in people in their 20s and 30s.

What Are the Symptoms?

The symptoms of SAD are severe and usually appear around September or October and continue until March or April. They are similar to the symptoms of depression, including decreased energy, excessive sleepiness, or fatigue. In some cases, a person has feelings of sadness and a decreased interest in sex or physical contact. He or she may withdraw from family and friends. Many people with SAD gain weight, perhaps because of an increased appetite and a craving for carbohydrate-rich or sugary foods.

The symptoms subside in the spring and summer, either gradually with increasing sunlight or suddenly. Some people experience bursts of energy or creativity or elevated moods during this time, similar to the manic episodes that occur in bipolar disorder.

How Is SAD Diagnosed?

A diagnosis of SAD can usually be made after two or more consecutive winters of symptoms of depression that go away when the weather turns warmer and daylight increases. People with SAD may notice that their symptoms recur or worsen if the amount of indoor light they are exposed to decreases or if the weather is overcast at any time of year. A doctor may recommend a thorough physical examination and laboratory tests to rule out other possible conditions. If your doctor thinks you may have SAD or another type of depression, he or she will refer you to a mental health professional who has experience treating the various forms of depression, including SAD.

How Is It Treated?

Light therapy (phototherapy) provided by a fluorescent light box or by wearing a visor with a fluorescent light attached is commonly used to treat SAD. The amount of light needed to provide effective therapy varies from one person to another. Phototherapy usually is done in the morning or early evening to extend the feeling of daylight. Your doctor will monitor the therapy carefully because of possible side effects such as eyestrain, headache, and insomnia.

If you have SAD, try to expose yourself to daylight as much as possible. Outdoor light, even on a cloudy day, is brighter and can provide more light than a light box. Daily exercise can be helpful in treating SAD and is especially beneficial when done outdoors. Eating a balanced diet can help offset cravings for carbohydrates and sweets.

Antidepressant medications may be effective in eliminating or at least reducing the symptoms of SAD. Psychotherapy can often help people with SAD deal with their depression. Some people benefit from a combination of light therapy, medication, and psychotherapy.

Other Types of SAD

Many people gain weight and lack energy at times in the fall and winter. This mild form of SAD, called winter depression or winter "blues," is a more moderate reaction to seasonal variations in light than SAD and often occurs around the time of the winter solstice (December 21st). Some people who think they have the winter blues may simply be coming down with the holiday blues, a time when they are likely to eat more.

A reverse form of SAD, called summer depression, is characterized by irritability, insomnia, and decreased appetite with accompanying weight loss. Symptoms of reverse SAD may be related to the excessive heat of summer rather than a reaction to light.

If you think you may have seasonal affective disorder, don't ignore it. Talk to your doctor. Like any other form of depression, SAD can significantly impair your quality of life.

About the Book:

American Medical Association Family Medical Guide, Fourth Edition (Wiley; 2004; ISBN: 0-471-26911-5; Cloth/$45.00) is available at bookstores nationwide, major online booksellers, or direct from the publisher by calling 800-225-5945. In Canada, call 800-567-4797.