By: Dr. Alexia Georgousis ND   Living in Canada, most of us have heard of Seasonal Affective Disorder also known as the winter blues. SAD was described in the 1984 by Dr. Norman Rosenthal MD and has been studied for many years.  The exact etiology of SAD has not been determined.  Oddly enough, women are four times more likely to develop SAD than men. There is evidence that SAD symptoms during the winter are correlated with a lack of outdoor (environmental) light. When we don’t get enough outdoor light, our bodies do not produce enough serotonin and melatonin.  Serotonin is a chemical and neurotransmitter that is believed to play an important role in mood, appetite, social behaviour as well as sleep and sexual function. It is found in the brain, blood and bowel.  Melatonin is a hormone produced mostly by the pineal gland in the brain and is strongly linked to our sleep wake cycle (circadian rhythm).  The amount of melatonin secreted is inversely related to the amount of light the retina receives. It makes sense then that SAD is generally more prevalent in the winter and especially in areas further from the equator.  However, there is a much less common form of SAD that occurs in the summer and is thought to be connected to too much sunlight. Go figure?! […]