Definition and Symptoms

SAD is a recurrent major depressive disorder with a seasonal pattern, typically beginning in fall and continuing into the winter months. Symptoms include persistent low mood, loss of interest in usual activities, fatigue, sleep disturbances, changes in appetite, and difficulty concentrating.

Causes and Risk Factors

The exact cause of SAD is unknown, but it's believed to be linked to reduced exposure to sunlight during the shorter days of the year. This can affect your body's internal clock and lead to feelings of depression. Risk factors include living far from the equator, family history, and having another mood disorder.