So sad to have SAD this winter.

If you tend to become depressed in winter in the northern climes, with the short, dark days, it may he SAD -- seasonal affective disorder. SAD sufferers experience all kinds of problems in the winter, usually relieved by the time March rolls around: difficulty getting up in the morning, feeling lazy during the day, not doing their work as well, eating more (especially fattening foods) and thereby gaining weight from overeating and underactivity. School kids may find their performance below par and not get along with their friends.

The National Institute of Mental Health estimates that some 10 to 25 million Americans may be affected with SAD -- women four times as often as men. The diagnosis is not easy to make, however, because symptoms resemble other forms of depression; Psychiatrists limit it to persons with fall and winter depression for at least two years, without depression in spring and summer; at least one disabling depressive episode; no major psychiatric disorder, and no other explanation for the mood change.

The conventional wisdom, formerly shared by many scientists, has held light deprivation as the culprit, with light therapy as the obvious solution -- and all kinds of gadgets are available to provide the light, including bedroom lamps that switch on while it's still dark and slowly get brighter, lighting up the room as the sun would. Unfortunately, no studies have conclusively shown that light therapy is generally beneficial, nor can doctors predict whom it may help and whom it may not -- and many health professionals no longer consider it useful. Nonetheless, many SAD sufferers swear by it, and if the diagnosis is made by a doctor, there are medical insurance companies who will pay for some of the available gadgetry.

Suggestions for SAD sufferers include:

* Getting up at the crack of dawn

* Brightening up the house in the winter by whatever means

* Sitting near a window wherever possible at work or school

* Getting outdoors as much as possible

* Taking winter vacations in sunny places.

Finally, contact the support group NOSAD at P.O. Box 40113, Washington, DC 20016.