What is SAD?

SAD is a recurring prolonged period of depression, whose onset and remission coincides with changes in the seasons. In most cases the depression begins in late fall or early winter and persists until spring or sometimes even into summer. Slightly more women than men report suffering from SAD, and the majority of those afflicted with SAD are under the age of 40.

According to Dr. Kathleen B. Speicher of the Student Health Center, Indiana University—Purdue University Indianapolis, the common symptoms of SAD include "a change in appetite (especially a craving for sweet or starchy foods), weight gain, a heavy feeling in the arms and legs, a drop in energy level, fatigue, a tendency to oversleep, difficulty concentrating, irritability, increased sensitivity to social rejection and avoidance of social situations (hibernation)."

Some scientists believe that it is not so much the reduced number of daylight hours which promotes the onset of SAD, but rather the winter sunlight itself being less intense, often further diffused by heavy cloud cover. Others theorize that waking up on winter mornings prior to sunrise upsets the body's internal "clock," which is believed to be "synchronized" to local time through exposure to morning daylight. Still other researchers suggest that SAD may actually be the result of a combination of these effects, or even other effects that have not yet been identified.

About 20 years ago, it was first demonstrated that exposing humans to high-intensity light could actually bring about positive changes in the brain chemistry and help to counteract feelings of depression. So it was theorized that exposing people to increased amounts of intense light in the wintertime might have a similar beneficial effect upon those suffering from winter depression. And subsequent research has conclusively proved that light therapy does indeed significantly help many who suffer from SAD.

One study, reported in the Archives of General Psychiatry (October, 1998), was conducted by Dr. Charmane Eastman of Rush-Presbyterian St. Luke's Medical Center in Chicago. According to a report of her study on ABC News, "61 percent of people who got morning light therapy and 50 percent of people who got evening light therapy experienced nearly complete recovery from their seasonal depression after four weeks of treatment."

Another prominent researcher, Dr. Raymond W. Lam, described the current recommended procedure for administering light therapy in the October 2002 issue of Psychiatric Times. "The recommended protocol for light treatment," he explained, "is 10,000 lux exposure, administered by a fluorescent light box with an ultraviolet filter, for at least 30 minutes per day in the early morning (Lam and Levitt, 1999). Less intense light usually requires greater duration of exposure for the same response, e.g., 3,000 lux for one to two hours." Dr. Lam commented that improvement is often noted after only one week, with most patients noticing improvement within 2 to 4 weeks. Patients generally suffer relapse after the treatments are stopped, so they must be continued until the time of year when the symptoms of SAD would otherwise have subsided without light therapy.

Another promising new line of research involves the treatment of SAD by exposure to high-density negative ions. Negative ions are negatively charged molecules of air that occur naturally in the environment. Winter air generally contains a far lower concentration of negative ions than summer air. There is also evidence to suggest that the concentration of negative ions in the air may have an effect on serotonin levels in the brain. So it seemed reasonable to a number of researchers that enhancing the amount of negative ions in the air might also have a beneficial effect on winter depression.

As reported in the January, 1995 issue of the Journal of Alternative and Complementary Medicine, 58% of those in the Terman study receiving the high-density negative ion treatment reported that symptoms of winter depression were actually reduced by 50% or more without any side-effects. The researchers concluded that "treatment with a high-density negative ionizer appears to act as a specific antidepressant for patients with seasonal affective disorder. The method may be useful as an alternative or supplement to light therapy and medications."

In a follow-up study by the Termans, according to an October 14^th, 1998 report by ABC News, they "compared light therapy to treatment with high- or low-density negative ion emitters." The Termans "found that light-therapy patients did 30 percent better than those who got the low-density ions. Patients who got high-density ions did just as well as light-therapy patients, indicating that the high-dose ions might also be helpful in treating SAD."

A Columbia University spokesperson summarizes what has been learned so far about negative ions as a treatment for SAD. "Summer air, in contrast to winter air, is highly concentrated with negative ions. The negative ion machines we use are designed to mimic summer-like conditions by supplementing the sparse winter ion supply. We are finding that this evokes beneficial mood effects. Although the ions emitted from the machines are not perceptible to your senses, studies have indicated clear improvement in patients with winter depression."

There is still much yet to be learned about the connection between SAD, light and negative ions. What is the optimum intensity vs. duration vs. time of exposure to light for best results in attempting to treat SAD? Why does exposure to high-density negative ions seem to be about as effective as light therapy? What concentration of negative ions would be optimum? What about combining both light and negative ion therapies to treat SAD, and in what proportions? The full answers to these questions are not yet known. It is therefore a field that researchers are continuing to actively investigate.

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