Seasonal Affective Disorder is a kind of winter depression that spans the months of November to March.   It is caused by a biochemical imbalance in the hypothalamus thought to be due to the lack of sunlight in the winter months.  People living in the northern and southern hemispheres are often susceptible, while people living near the equator are seldom diagnosed with SAD.

 

Its symptoms mimic those of depression with the exception of the seasonal aspect.  People with SAD experience abnormal fatigue, irritability, food cravings and weight gain, and the desire to avoid socializing.  Some will suffer from esteem issues, loss of feelings, and intolerance to stress.  Some sufferers have only mild symptoms while others find it debilitating.

 

With the coming of the spring and more light, the symptoms disappear.  An accurate diagnosis of SAD can be made by observing the pattern of the onset and lifting of depression over a three year period.

 

For treatment, full spectrum light therapy is effective in most cases.  The intensity of the light must be many times the brilliance of ordinary household lighting.  The use of a lightbox for three or four hours a day has an 85% success rate.  Other treatments include ion generators, some anti-depressant medications and cognitive therapy.