When the weather begins to chill, we observe changing leaves and shorter days. The shift is delightful for the most part. However, in many parts of the country there is a very distinct reduction in the amount of natural light available, which has been known to have a powerful effect on some people. The official name for the condition is seasonal affective disorder, or SAD. It is a kind of depression related to the change in seasons, typically starting in the fall; the brain becomes confused when our circadian rhythms, or body clock, are off due to changes in sunlight. More women are diagnosed than men, but men tend to experience more severe symptoms.