It forces us to rethink the way we light up our lives, especially urban dwellers and workers who spend so much time indoors. Apparently artificial light does much more than enable us to read and work without benefit of sunlight. It affects our bodies. We have measured some very interesting physiological changes specific to this kind of depression. While typically depressed people have impaired sleep patterns and usually wake up early, winter depressives might sleep nine or 10 hours a night, wake up tired, and take naps.
Winter depressives gain weight, crave carbohydrates, and their libido pales.
Such symptoms begin earlier the farther north they live and abate. When they visit sunny southern climates in the winter. Symptoms peak and wane according to the length of days. Such a distinct seasonal pattern implicates the external environment as the culprit, the most obvious being sunlight. Sunlight has already been shown to trigger cycles and seasonal behavior in animals, including reproduction, hibernation, migration, and molting.