Seasonal Affective Disorder (Sad)
Author: michaelrussell
Author: michaelrussell
Few people look forward to the gray days and long, dreary nights of winter. In fact, most people feel better in the summer, when the days are longer, sunnier, and warmer. We get out more, exercise harder, and eat less. But for some people, the transition from summer to winter is much more than a slight disappointment. It is nothing short of a nightmare. For these individuals, the change in seasons signals a marked change in personality from happy and relaxed to depressed and tense. Getting out of bed in the morning becomes a major effort, food (especially carbohydrates) becomes a major attraction, depression looms constantly, concentrating becomes all but impossible, and irritability runs rampant. Then, just when they think life isn't worth living any more, spring comes along and they are suddenly back to their old selves again.
Until ten years ago, people suffering from this seasonal change in personality had no idea what was wrong with them. But then Norman E. Rosenthal, M.D., author of Seasons of the Mind, made the connection between the shorter, darker days of winter and the onset of seasonal depression. He and his colleagues began studying this phenomenon and gave it the name seasonal affective disorder (SAD). As for what actually causes SAD, the experts aren't exactly sure. "Just what it is about the light deficiency that creates the low mood is the question. And while we don't have a final answer yet, we do have several theories," says David H. Avery, M.D., associate professor of psychiatry and behavioral sciences at the University of Washington School of Medicine, Harborview Medical Center, in Seattle. "One such theory suggests that there is a delay in the timing of the body clock in sad patients that causes their temperature minimum to occur at 6:00 A.M. rather than at the normal time of 3:00 A.M. As a result, they are attempting to wake up when physiologically it is the middle of the night," Avery says. "When we treat these people with bright light from 6:00 A.M. to 8:00 A.M., we not only improve their mood, we also see a shift in their temperature minimum to an earlier time. Using the light in the morning creates a phase advance," he adds.
Another theory is that the secretion of the hormone melatonin is responsible for the low mood and lack of energy. "It is known that the hibernation and reproductive cycles of animals are regulated by the secretion of melatonin. Melatonin is only secreted in the dark and is very light sensitive," says Avery. "During the long summer days, melatonin secretion is markedly reduced because the nights are shorter. But during the long winter nights, melatonin secretion increases," he explains. "Human melatonin production is also responsive to light, but it takes much more light to stop that production than it does in animals," says Raymond Lam, M.D., a psychiatrist in the Mood Disorders Program at the University of British Columbia in Vancouver.
"When melatonin is administered to normal individuals, it tends to lower their body temperature and cause drowsiness. So one initial thought about winter depression is that people who have it are secreting a lot of melatonin during the winter and not much during the summer," adds Avery. With this theory, the light therapy is thought to work because it shuts off the melatonin production. Still, these and other theories have yet to be proven. And sad can hit in varying degrees. In one study, 75 percent of the subjects had sought treatment for their depressions. "I have even had patients who have been hospitalized every winter," says Avery. Still, others say that they don't feel all that depressed, they simply have such low energy that they aren't able to accomplish the things they would like to accomplish. For most people with SAD, it takes two or three jays of bright sunshine to elicit a reversal of symptoms. And, consequently, a tip off that you may have it is if you find great relief in your symptoms when traveling toward the equator.
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