Here’s What to Know About Summertime Sadness (S.A.D.) June 5, 2018 – While classic winter S.A.D. is confusing, summer SAD is even trickier. By most estimates, between 5% and 10% of the U.S. population experiences S.A.D.,,Seasonal Affective Disorder.  But only a small portion of Americans, somewhere around 1% of the total population, have flare-ups in the summertime, says Dr. Norman Rosenthal, a SAD expert and a clinical professor of psychiatry at the Georgetown University School of Medicine. Whenever it occurs, SAD can be a difficult condition to diagnose. It’s defined as major depression that follows a seasonal pattern for at least two years, according to the National Institutes for Mental Health. But since it’s a subtype…