The Collaborative International Dictionary
seasonal affective disorder \seasonal affective disorder\, n. A form of mild depression that occurs in winters, associated with reduction in the amount of sunlight. It is characterized by oversleeping, irritability, and sometimes overeating. It can be treated by light therapy and usually disappears with the arrival of spring.
Wiktionary
n. (context pathology English) A form of depression associated with the lack of natural light during the winter months.
Wikipedia
Seasonal affective disorder (SAD), also known as winter depression, winter blues, summer depression, or seasonal depression, is a mood disorder subset in which people who have normal mental health throughout most of the year experience depressive symptoms at the same time each year, most commonly in the winter.
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 treatments for classic (winter-based) seasonal affective disorder.
Usage examples of "seasonal affective disorder".
The weather, with its constant overcast, is such that 943 out of the 1,006 people on this expedition have had to be treated for the form of depression known as 'seasonal affective disorder.
Shaftoe and Bischoff, both mired in the yet-to-be-discovered emotional dumps of Seasonal Affective Disorder, are like two brothers trapped in the same pit of quicksand, each keeping a sharp eye on the other.
During the wintry depths of his depression, his seasonal affective disorder in Elton, New Mexico, Dr.
The fact that the place was like an experimental environment for inducing seasonal affective disorder may also have been a subconscious factor.
Every autumn during her adult life, she fell ill with a variety of symptoms - modern doctors might well conclude that she suffered from a seasonal affective disorder.
There was even a medical name for the condition: seasonal affective disorder.