MENTAL HEALTH: LIGHT TREATMENT
In 1979, Dr. Al Lewy, now professor of psychiatry at Oregon Health Sciences University in Portland, and Dr. Wehr began work on a hormone called melatonin, released by the pineal gland in the brain. Their studies revealed that light plays an important role in triggering and setting the biological clocks in animals. Other studies showed that exposure to light stops nighttime production of melatonin in the pineal gland. Dr. Lewy, Dr. Wehr, and their colleagues have found that nighttime melatonin production in humans can be stopped with 2,500 lux-intensity light. (Lux, Latin for light, is the unit of measure for brightness.) This suggests that such brightness could be used to reset human biological rhythms.
It was their melatonin work that brought Herb Kern to the National Institute in 1980. He asked Dr. Lewy to measure his melatonin levels. Mr. Kern, an engineer, had an undiagnosed case of SAD. He had kept records on his mood changes for 15 years and had told his doctors that, as the days got shorter, he “just wanted to crawl into a hole and hibernate.” Mr. Kern recalls, “I finally latched on to the thought that sunlight was the key. When the days got longer in summer, the wheels of my brain would spin again.” But, he says, his doctors didn’t listen to him.
Dr. Lewy suggested lengthening Mr. Kern’s winter days by sitting him in a room under bright fluorescent lights for 6 hours – three before dawn and three after sundown. Within days, Kern reported feeling as if springtime were around the corner. He still takes 2 hours of light treatment at 6 A.M. from fall to spring. “Since using the lights, I have been able to manage my depressions very nicely,” he says.
The doctors spent the next few years focusing on the effects of light on mood and wanted to extend the study with more patients. Dr. Rosenthal told a reporter from the Washington Post about Mr. Kern and another patient. When the article was printed, thousands inquired about treatment. That was the first hint that SAD was a common disorder. With a selected group of patients, the doctors showed that light relieves wintertime depression. They also found that the brighter the light, the shorter the SAD treatment. Since then, studies worldwide have demonstrated the same, and the American Psychiatric Association now lists seasonal mood swings as a form of mental disease.
In New York, Dr. Terman has a new computerized approach: creating an artificial dawn. In phototherapy, “we were turning on very bright light suddenly after the patient wakes up,” he says. “But when the eye is adapted to the dark while sleeping, it is ‘looking’ for a gradual transition to dawn. We put computer systems in a patient’s bedroom to gradually turn on a light from very dim to bright, like a sunrise. Within a few days, we got results equal to any effect of bright-light therapy. The patients wake up spontaneously, refreshed. “
Dr. Terman says he tried it, because he detects seasonal changes in energy level and sleep in himself: “I maintained a summer sunrise throughout winter and was not groggy. It is a natural alarm clock.”
Scientists already have shown that exposure to light can reset the biological clock if work shifts change or jet lag strikes. Some people have delayed sleep – biological clocks that won’t let them go to sleep before 2 A.M. Others have advanced sleep and can’t keep their eyes open after sundown. Light treatment can reset both.
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GENERAL HEALTH