Home > Encyclopedia of Alternative Medicine > Seasonal Affective Disorder

Definition

Seasonal affective disorder (SAD) is a form of depression most often associated with lack of daylight in extreme northern and southern latitudes from the late fall to the early spring.

Description

Although researchers are not certain what causes seasonal affective disorder, they suspect that it has something to do with the hormone melatonin. Melatonin is thought to play an active role in regulating the "internal body clock," which dictates when humans feel like going to bed at night and getting up in the morning. Although seasonal affective disorder is most common when light is low, it may occur in the spring, which is often called reverse or spring-onset SAD. Recent research also indicates that SAD has a genetic factor; about 29% of cases in the United States run in families.

Causes & symptoms

The body...