Lighten up While the exact cause of SAD is not known, people with the disorder can bask in the cheerful news that SAD is generally more easily treated than clinical depression. The standard treatment is light therapy. Researchers are not exactly sure how it works, but one theory is that the lack of sunlight causes the body to produce more melatonin, a hormone that helps regulate seasonal rhythms and sleep. This excess melatonin may in turn cause serotonin deficiencies linked to depression. Exposure to light seems to diminish the effects of this process.
Many patients do well with light therapy.
Rosenthal advises people not to stare into the light, but instead to read or work at their desk. They can even run on a treadmill. Although popular, Rosenthal is not in favor of using the smaller light boxes. They are not as effective or well researched as the larger light boxes, which typically cost several hundred dollars. Another light therapy device is a dawn simulator that attaches to a bedside lamp and gradually simulates the rising of the summer sun.