Seasonal Affective Disorder (SAD) is a recurring type of depression that begins in the Fall and continues through Winter, but tends to go away with the sunnier days of Spring and Summer. It is believed to be a result changes in the amount of sunlight that affects your internal biological clock (circadian rhythm), which can affect your sleep patterns and serotonin levels. There are other factors that begin in the Fall, which impact mood and behavior. With the colder temperatur