Seasonal affective disorder (SAD) is a specific type of depression, one much graver than a simple case of the winter blues, says Norman Rosenthal, MD, the world’s leading expert on the disorder and author of Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder. But how can you know the difference between SAD and other types of depression?
For starters, SAD emerges almost like clockwork, usually after the shift to Daylight Savings Time: As the days get shorter and the light more scarce, your body’s biological clock can get thrown off.