Exposing people to carefully timed bright lights can reset the biological clock, helping people overcome jet lag or cope with the stresses of shift work. Today, even conventional doctors are accepting these and other therapeutic uses of light therapy . Many people complain about feeling down, having less energy, putting on a few pounds, and having difficulty getting up in the morning throughout the dark short days of winter. People suffering from SAD experience these and other symptoms to such a degree that they feel unable to function normally. They often feel chronically depressed and fatigued, and want to withdraw from the world and to avoid social contacts.
Women frequently report worsening of premenstrual symptoms.
People with SAD suffer in the extreme the kinds of changes which others may suffer to a much lesser degree in wintertime. An individual SAD sufferer, however, need not show all the symptoms described above. Sleep duration, for example, may be normal, while carbohydrate craving may be extreme, or vice versa. Sometimes a symptom in the cluster is actually opposite the norm, such as insomnia as opposed to excessive sleep. These people notice the return of SAD-like symptoms each winter, and are bothered by them, but remain fully functional.