What is Seasonal Affective Disorder? What Is SAD?

Seasonal Affective Disorder, also known as SAD, is a type of depression that occurs in countries that are far away from the equator during the winter months. SAD is sometimes called winter depression. As the mornings start later and evening begin earlier when winter approaches, there is less total sunlight each day. Experts say SAD is most likely caused only by lack of sunlight, and not cold temperatures. Depressive symptoms usually build up slowly as days start getting shorter, and gradually subside in early spring, as the amount of environmental sunlight each day rises.