The Nightingale Center

What is Seasonal Affective Disorder?

By Lois V. Nightingale, Ph.D.

During the fall and winter months many people notice feelings of fatigue, low energy, anxiety, agitation, a low frustration tolerance, or a general feeling that life is a burden and they feel hopeless about changing it. These feelings may not come from spending holidays with relatives or pressured gift buying. They may have a very specific biological cause: Seasonal Affective Disorder.

Although S.A.D. was first noted before 1845, it has only recently received wide public attention. S.A.D. is a form of depression with symptoms that occur during the winter months, usually going into remission during the spring and summer. In a few people there may be reoccurring summer depressive episodes. But most people with S.A.D. find that they are symptom free during summer months but find themselves spiraling down into depression when the days become shorter. For people with S.A.D. January and February are usually the worst months.

Causes:

It has long been known that as sunlight changes throughout the year it affects many seasonal activities of animals, such as food gathering, hibernation, nesting and reproductive cycles. Apparently, humans are no exceptions. People are also affected by the reduction of light during winter months. The prevalence of S.A.D. also seems to vary with the latitude in which a person lives, sex and age. The occurrence of S.A.D. increases at higher latitudes. Women seem to comprise 60-90% of sufferers. And many people with the disorder often began to notice symptoms in early adulthood.

Researchers have tied S.A.D. to melatonin, a sleep-related hormone that the human pineal gland produces and releases in the dark. The production of this hormone seems particularly active during winter, when the days are shorter and darker. This may be one of the causes of the fatigue and over-sleeping (hypersomnia) that often accompanies S.A.D.

Symptoms:

• Regularly occurring symptoms of depression (fatigue, sleeping more than usual, sad, anxious or "empty" moods; decreased energy and interest in things, etc.) during the fall/winter months of at least three different years-two of them consecutively.
• At least three times as many instances of depression within a two-month time frame as during other times of the year.
• No other seasonal factors that could account for regular mood changes (seasonal job, school schedule, etc.).
• Excessive eating, weight gain and the craving of carbohydrates.

Treatment:

In 1980, a researcher named Dr. Alfred Lewy discovered that very bright light blocks the release of melatonin in people, and relieves winter depression. Patients with SAD generally respond to bright light therapy within four days of starting treatment, but have symptoms return within four days after stopping the light therapy. Because so many people respond to bright light treatment, it's assumed that light has an antidepressant effect.

(Statistics from the National Mental Health Ass. and the Diagnostic & Statistical Manual of Mental Disorders-IV.)

For further information on this topic you can read:

Seasonal Affective Disorder: Who Gets It, What Causes It, How to Cure It
By Angela Smyth, Chris Thompson

© 1997 Lois V. Nightingale, Ph.D., Clinical Psychologist and director of the Nightingale Center in Yorba Linda, 714-993-5343.