Symptoms usually surface in childhood or adolescence.
Researchers believe that SAD results from the shorter day length in winter. Recent studies estimate that SAD is more common in northern countries because the winter day gets shorter as you go farther north. For example, in Florida, less than 1 percent of the general population are estimated to have SAD, while in Alaska as many as 10 percent of people may suffer from winter depression. Children with SAD exhibit irritability, difficulty getting out of bed and school problems in fall and winter. Keep the curtains open.