In 1984, while a researcher at the National Institutes of Health, Norman Rosenthal first identified Seasonal Affective Disorder (SAD) and pioneered light therapy to treat the condition. People with SAD, sometimes called winter depression, begin to feel down in the fall or early winter as the days grow shorter, then make a full recovery come spring. For some, the disorder can be a relatively minor episode of “winter blues.” For many, though, it is a recurring bout of clinical depression that demands immediate medical care.
But SAD isn’t just a winter visitor. Some people experience what is called summer SAD, summer depression, or reverse SAD. It’s less common — only about one-tenth as common as its cold-weather counterpart — and less well known. However, it can be just as dangerous.
