Seasonal Affective Disorer (SAD), also known as the winter blahs or winter blues, is a not uncommon conditon (incidence varies with  the geographic location one lives) in which a person notes changes in moods with changes in season. The most common manifestation is the emergence of recurrent depressive episodes beginning in the fall and worsening in the winter as a result of the decrease in photo-stimulation by the sun which is then thought to effect serotonin, melatonin and Vitamin D levels in the body. Not only are the days shorter, but the sun is farther away from the planet so light intensity is decreased. Also, one be outside less as a result of the colder weather. Common symptoms of SAD include lowered energy, increased need for sleep and increased appetite with carbohydrate cravings. In more severe cases, anti-depressant medication may be recommeded. Other therapy recommendations would include light therapy in which one would sit in front of a light box with a light intensity of at least 10,000 Lux for 20-45 minutes per day, getting out as much as possible, having a well light work and home environment, exercise and Vitamin D supplementaion. One could also go on a vacation to a geographic area closer to the equator i.e. Hawaii.