Seasonal Affective Disorder (SAD) Explained

Seasonal depression, also known as seasonal affective disorder or S.A.D., is a subtype of major depression with seasonal changes.

It typically onsets in the autumn, lasts through the winter months and improves in the spring. Dr. Gloria Petruzzelli, a clinical psychologist at UC Davis Health, explains the difference between "winter blues" and seasonal affective disorder, as well as the symptoms, warning signs and treatments.