Employee Assistance Program → Topics and Tips → Seasonal Affective Disorder (SAD)
About 11 million Americans have Seasonal Affective Disorder (SAD), a severe form of winter depression that is related to variations of light. SAD was first noted before 1854 but not officially named until the early 1980's.
As seasons change, there is a shift in your circadian rhythm (internal clock) due partly to alterations in sunlight patterns; in the winter months, the days are shorter and darker. The lack of sunlight causes the brain to work overtime producing melatonin, a hormone found in the pineal gland. Melatonin regulates your body clock and sleep patterns. It has also been linked to depression.
NIH, National Mental Health Association, Biological Psychology 2nd Edition, Winter Depression Program at New York Psychiatric Institute/Columbia University Medical Center, and Washington and Shady Grove Adventist Hospitals. The Health Tip of the Week is for educational purposes only. For additional information, consult your physician. Please feel free to copy and distribute this health resource.