Seasonal Affective DisorderWhen a case of the winter blues feels more like depression, you may be suffering from SAD. SAD stands for Seasonal Affective Disorder. SAD is a seasonal mood disorder that occurs during the winter months and ceases with the onset of spring. Symptoms usually begin in September, when the days begin to get shorter, and last throughout the winter until March, when the days begin to get longer again. Symptoms of SAD usually include episodes of depression, hypersomnia, increased appetite, and weight gain. Light plays an important role in its origin and treatment. To better understand the winter blues, think of it as four months of jet lag. The human body has hundreds of 24-hour biological rhythms, all controlled by an "internal clock." The sleep cycle is a rhythm. Body temperature is another. Another is the brain's production of certain chemicals, such as melatonin, the nocturnal hormone. Melatonin is a hormone produced by a gland in the brain called the pineal gland. High levels of this hormone can negatively affect our mood. Very little melatonin is secreted in daylight and its peak production usually occurs at night, between 2 and 3 am. Due to longer nights, the winter months cause extra melatonin production in the body. In the summer, most of us wake up when it's light outside. Morning light decreases melatonin levels in the body. In winter, however, most of us struggle to wake up while it's still dark outside. Darkness causes increased melatonin levels, which causes depression in some people. Seasonal affective disorder causes many symptoms of depression. It may cause a decrease in interest or enthusiasm in all, or nearly all... half of the article ......raphy: Bibliographic information: American Academy of Family Physicians (March 15, 1998). “Seasonal Affective Disorders,” URL http://www.aafp.org/aft/980315ap/saeed.html (accessed 1:19 p.m., May 11, 1999). Chamberlain, Claudine. “SAD Scientists See the Light,” URL http://abcnews.go.com/sections/living/InYourHead/allinyourhead_13.html (accessed 1:12 p.m., May 11, 1999). Outside In Company. “Outside in SAD Information Sheet,” URL http://www.outsidein.co.uk/sadinfo.htm (accessed 1.05pm, 11 May 1999). Solar Brite. “Seasonal Affective Disorder: Solution to SAD-Winter Depression,” URL http://www.healthtechnologies.com/solarbrite/solution.htm (accessed 1:36 p.m., May 11, 1999) Thrive@Health. “Seasonal Affective Disorder,” URL http://www.thriveonline.com/health/Library/illsymp/illness470.html (accessed 1:30 p.m., May 11, 1999).