3.What Causes SAD?
Doctors think less sunlight at certain times of year can trigger your body to change the way it makes and uses certain key brain chemicals. It may be that fewer daylight hours raises levels of melatonin and lowers levels of serotonin, two substances that help keep your sleep regular and your mood even.
4.Who Gets SAD?
The farther you are from the equator, the more likely you are to have SAD. For example, you’re about seven times more likely to get it if you live in New Hampshire than in Florida. Anyone can have the condition, but people with a family or personal history of depression get it more and their symptoms are often worse. And women get it four times more than men.
