Seasonal Affective Disorder (SAD)
en español: Trastorno afectivo estacional
Medically reviewed by: Lisa M. Buckloh, PhD
Also called: SAD, Seasonal Depression
What Is Seasonal Affective Disorder?
Seasonal affective disorder (SAD) is depression that happens only at a specific time of year. With SAD, a person becomes depressed in fall or winter, when days are shorter and it gets dark earlier. SAD is brought on by the brain’s response to the seasonal changes in daylight. When the daylight hours grow longer again, the depression lifts.