Sometimes called the Winter Blues, Seasonal Affective Disorder (SAD) is a mild depression that comes with the shorter, darker days of late autumn and wintertime. The individual may feel little ambition and energy, sleep excessively, overeat, and show other symptoms of depression. However, when the sun returns to lengthen the days, the problem seems to lift and normal mood and functioning reappear.
Obviously, seasonal changes do not affect people to the same degree. SAD affects women more than men by a 4:1 ratio. Some ethnic groups are more affected than others. It is progressively more common with distance from the equator. This last fact has brought attention to the effect of the sun, or light, as a critical variable. It is now an accepted fact that limited exposure to full-spectrum light is key, and effective treatment uses “light therapy” as a primary remedy.
Some interesting research has resulted. In controlled studies, people with SAD often show remarkable improvement from only one or two short (30 minute) sessions of light therapy. Some studies have shown effective results even from light exposure to the back of the knee or other isolated parts of the body, suggesting a subtle body chemistry imbalance is the culprit -- perhaps something in the blood itself.
While talk therapy and antidepressant medication is not usually needed (or effective) for SAD, it is important not to self-diagnose this problem. If you believe you are prone to SAD, contact a professional who can help differentiate among the many varieties of depressive illness.