Photo by Camila Quintero Franco on Unsplash

Seasonal affective disorder (SAD) is a type of depression that occurs at a certain time of year, usually in the fall or winter.

It is not clear what causes SAD, but it is thought to be related to the change in daylight hours and the decrease in sunlight exposure; which can disrupt the body's circadian rhythm and lead to fatigue, difficulty concentrating, changes in appetite, and feelings of hopelessness and despair.