SAD

,,,,,Doctors have recently started to study the causes of a medical disorder that they have approximately named SAD, of Seasonal Affective Disorder. People who suffer from SAD become very depressed during the winter months.
,,,,,The depression appears to be the result of a decrease in the amount of sunlight they are exposed to. Doctors believe that a decrease in the amount of sunlight the body receives may cause disturbance in the body's natural clock which could result in symptoms such as lethargy, oversleeping, weight gain, anxiety, and irritability - all signs of depression.
,,,,,Since absence of light seems to be the cause of this order, doctors advise patients to sit in front of a special light box that stimulates natural light for a few hours every day.