Seasonal+Affective+Disorder

listen [|here] Listen to the passage. On a piece of paper, take notes on the main points of the listening passage. (professor) Something that affects some residents of Alaska and other societies in the far north of the globe during the winter months is a disorder call SAD. SAD is actually an acronym S-A-D,and it stands for seasonal affective disorder. "S" for seasonal, "A" for affective, and "D" for disorder. In the summertime, Alaska is blessed with a tremendous amount of sunshine, 20 hours of sunshine a day in Anchorage and 22 hours of sunshine a day in Fairbanks. In the winter, however, the opposite occurs, and there are long, long hours of darkness and only an occasional few hours of sunshine if the sky during the hours when sunshine is possible isn't cloudy or stormy. During these long periods of darkness interrupted by little or no sunlight, residents can be afflicted by SAD, or seasonal affective disorder, a serious kind of clinical depression. Estimates of the percentage affected by SAD range from 10 to 20 percent of the population. There's actually a physiological cause of this disorder, one that's related to the lack of regular sunlight. When the human body receives less sunlight, it produces less serotonin and more melatonin than usual. Serotonin is a hormone that causes humans to feel cheerful and positive, and less serotonin is produced when there's inadequate sunlight. Melatonin is a hormone that causes humans to feel drowsy and fall asleep, and more melatonin is produced when there's inadequate sunlight. It's this combination of reduced serotonin and increased melatonin that's the cause of seasonal affective disorder in areas where sunlight is reduced considerably for several months at a time. WHAT POINTS DOES THE PROFESSOR MAKE ABOUT SAD? Topic: The professor lectures about Seasonal Affective Disorder in Alaska and other societies in the far north of the globe Main points: 1.SAD means clinical depression connected with seasons and sunshine. 2. In summer When the human body receives more sunlight, it produces more of hormone serotonin, that causes humans to feel positive. 3.In winter When the human body receives less sunlight, it produces more of hormone melatonin, that causes humans to feel sleepy and sick.