Seasonal Affective Disorder
This comprehensive overview by the Mayo Clinic covers symptoms and treatment of this depression type.

Seasonal Affective Disorder
An article at Wikipedia.

SAD Therapy Lights
These lights can alleviate the symptoms of Seasonal Affective Disorder.

Treatment With Light Therapy
An article by by the Mayo Clinic.

Seasonal Affective Disorder
Information about SAD from the American Academy of Family Physicians.