SEASONAL AFFECTIVE DISORDER
DEFINITION
Seasonal affective disorder (SAD) is a form of depression (see depression entry) most often associated with the lack of daylight. The condition usually occurs in the extreme southern and northern latitudes from late fall to early spring.
DESCRIPTION
SAD occurs in parts of the world where days are very short during some seasons of the year. In Alaska and parts of Canada, for example, there may be no more than a few hours of daylight during the winter months. During these periods, some people may become very depressed. That condition is known as seasonal affective disorder, or SAD. When SAD occurs in the spring, when there is more daylight, it is sometimes called reverse SAD.
Though SAD is not officially listed as a mental disorder by psychiatrists, some authorities think as many as ten million Americans may be affected by the condition. Another twenty-five million Americans may have a mild form of SAD, called the "winter blues" or "winter blahs." The farther a person lives from the equator, the more likely he or she is to develop SAD. Women make up the majority of people with the disorder.
CAUSES
Scientists are not sure what causes SAD, but a hormone known as melatonin may be involved. A hormone is a chemical that occurs naturally in the body and controls certain body functions. Melatonin (pronounced mell-uh-TOE-nin) is thought to act as an internal body clock, "reminding" people when to go to bed at night and when to get up in the morning. If the hormone does not function properly, a person's body rhythms may be disturbed, which could lead to depression.
The amount of melatonin produced by the body is partly a function of the amount of daylight the body is exposed to. The more daylight, the less melatonin the body makes. The less daylight, the more melatonin. Scientists know that our bodies produce more melatonin at night and during the winter, when days are short.
One function of melatonin is to make the body feel sleepy. Some researchers think SAD is caused by an excess of melatonin during the winter months. People with too much melatonin may feel tired and depressed.
Seasonal Affective Disorder: Words to Know
- Antidepressant:
- A drug used to prevent or relieve depression.
- Hormones:
- Chemicals that occur naturally in the body and control certain body functions.
- Melatonin:
- A hormone thought to control the body's natural sleep rhythms.
SYMPTOMS
The symptoms of SAD are similar to those of other forms of depression. People with SAD may feel sad, irritable, or tired. They may find themselves sleeping too much. They may also lose interest in normal activities and become withdrawn. A tendency to overeat and gain weight is another common symptom of SAD.
DIAGNOSIS
One step in diagnosing SAD is to eliminate other possible causes of a person's depression. A doctor also relies on the patient's description of his or her own symptoms, including the time of the year in which they occur.
TREATMENT
One obvious way to treat SAD is to expose a patient to a greater amount of light. One device used for this purpose is a light box. A light box contains a set of lights in front of a reflector. The light produced by this device is about fifty times as bright as ordinary indoor light. The patient sits next to the light box for about thirty minutes each session. The light box replaces a portion of the natural light that is absent in the winter months.
Light therapy is generally considered safe for most people. However, it may be harmful to people with eye disorders. The most common side effects of using a light box are vision problems, such as eye strain; headaches; irritability; and insomnia. In addition, a person may experience an excited mood after using the light box.
NIELS TYBERG FINSEN
It's easy to take the common things in life for granted. Sunlight is an example. We are so used to seeing sunlight that we may not realize how important it is to health. For example, sunlight helps the production of vitamin D in the skin. Vitamin D prevents bone disease.
One of the first scientists to study the effects of light on health was Niels Tyberg Finsen (1860–1903). Finsen was born in the Faroe Islands in the North Atlantic Ocean. The Faroe Islands are close to the Arctic Circle. They receive relatively little sunshine throughout the year.
When Finsen became a doctor, he decided to study the effects of ultraviolet light on biological tissue. He became convinced that light can be used to treat human disease. He invented a powerful lamp for the treatment of lupus vulgaris, a skin disorder. The lamp was called the Finsen light in his honor.
Some of Finsen's ideas were incorrect. For example, he mistakenly thought that light could be used to cure smallpox. But, overall, his research was very important. It led the way to using many forms of radiation, including X rays and gamma rays, to treat human disorders. For his work in this field, Finsen was awarded the 1903 Nobel Prize in medicine and physiology.
Another possible treatment for SAD that is being studied is injections of melatonin. Some researchers think that the hormone might help the body adjust to longer periods of darkness without causing depression.
Seasonal affective disorder may also respond to medication. The four classes of drugs used for the disorder are:
- Heterocyclic antidepressants (HCAs), such as amitriptyline (trade name Elavil)
- Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (trade name Prozac), paroxetine (trade name Paxil), and sertraline (trade name Zoloft)
- Monoamine oxidase inhibitors (MAO inhibitors), such as phenelzine sulfate (trade name Nardil) and tranylcypromine sulfate (trade name Parnate)
- Lithium salts, such as lithium carbonate (trade name Eskalith), often used by people with bipolar disorder
Counseling
Counseling can sometimes help people with SAD, by helping patients understand the cause of their disorder and how it can affect their interaction with other people.
PROGNOSIS
Most patients with seasonal affective disorder respond to light therapy and/or medications.
PREVENTION
SAD can be prevented by increasing one's exposure to natural light.
FOR MORE INFORMATION
Books
Peters, Celeste A. Don't Be SAD: Your Guide to Conquering Seasonal Affective Disorder. Calgary, Alberta: Good Health Books, 1994.
Rosenthal, Norman E. Winter Blues: Seasonal Affective Disorder: What It Is and How to Overcome It. New York: Guilford Press, 1998.
Taylor, Clifford A., and Robin Karol Levinson. If You Think You Have Seasonal Affective Disorder. New York: Dell Publishing Company, 1998.
Organizations
American Psychiatric Association. 1400 K Street NW, Washington, DC 20005. (202) 682–6000. http://www.psych.org.
National Depressive and Manic Depressive Association. 730 N. Franklin Street, Suite 501, Chicago, IL 60610. (312) 642–0049.
National Institutes of Mental Health. Mental Health Public Inquiries. 5600 Fishers Lane, Room 15C-05, Rockville, MD 20857. (301) 443–4513.(888) 826–9438. http://www.nimh.nih.gov.
Web sites
"Ask NOAH About: Mental Health." NOAH: New York Online Access to Health. [Online] http://www.noah.cuny.edu/mentalhealth/mental.html#SAD (accessed on October 31, 1999).