But childhood winter blahs and doldrums are much more common. In a recent survey of 1,700 children's mood changes, Mary Carsakdon, Ph.D., a professor of biomedicine in psychiatry at Brown University in Providence, Rhode Island, discovered that almost 50 percent showed at least one symptom of depression in winter, compared with only 10 percent in the spring and fall. O ther types of depression afflict many more women than men, and SAD is no exception. The NIMH estimates that women with SAD outnumber men four to one. The condition also seems to run in families.
Seasonal behavior changes in animals involve the light-sensitive pineal gland in the brain.
As the days grow shorter, the eyes transmit less light energy along the optic nerve, and the pineal gland releases more of the hormone melatonin, which helps regulate behavior. In some animals, the rise in melatonin suppresses reproduction, which has a significant survival advantage. It means that females and offspring are spared the hardship of delivering young or being born during the coldest, most physically stressful time of year. H umans also have light-sensitive pineal glands, but until recently, scientists didn't think people had seasonal rhythms. Now they know differently, and not just because of winter blues.