Seasonal affective disorder (SAD), also known as winter depression, winter blues, summer depression, summer blues, or seasonal depression, was considered a mood disorder in which people who have normal mental health throughout most of the year experience depressive symptoms in the winter or summer. In the Diagnostic and Statistical Manual of Mental Disorders DSM-IV and DSM-5, its status was changed. It is no longer classified as a unique mood disorder but is now a specifier called with seasonal pattern for recurrent major depressive disorder that occurs at a specific time of the year and fully remits otherwise. Although experts were initially skeptical, this condition is now recognized as a common disorder. SAD’s prevalence in the U.S. ranges from 1.4% in Florida to 9.9% in Alaska. The U.S. National Library of Medicine notes that “some people experience a serious mood change when the seasons change. They may sleep too much, have little energy, and may also feel depressed. Though symptoms can be severe, they usually clear up.” The condition in the summer can include heightened anxiety. SAD was formally described and named in 1984 by Norman E. Rosenthal and colleagues at the National Institute of Mental Health. There are many different treatments for classic (winter-based) seasonal affective disorder.