This time of year seems to make me depressed. While researchers haven't totally figured out these seasonal mood changes, they appear to be triggered by the lack of light.
Light reaches the brain through the eye and helps to control our internal clock.
For milder cases, I recommend aerobic exercise , especially outdoors during the winter. At least take daily walks , at midday if at all possible, when the light is strongest. Paint your walls a bright, reflective color, sit in sunny rooms, and avoid northern exposures if you can. And if you're a woman SAD sufferer who is considering having a baby, I'd suggest that you try to plan your pregnancy so that you deliver in the spring. SAD may only compound a case of postnatal depression.