And for many, this is a time of depression. Not the kind experienced on a non-regular or spontaneous timetable, but one that begins as the cold winter months approach and may not leave until the onslaught of Spring. This kind of depression has a specific name, and you may have heard of it: Seasonal Adjustment Disorder, or (appropriately initialed, SAD. It was identified approximately fifteen years ago. Dr. Norman Rosenthal at the National Institute of Mental Health did much of the pioneering work on SAD.
About 6% of the population is afflicted with SAD and it occurs in all age groups. Women, however, are four times more likely to suffer from SAD. SAD is often more common in the northern latitudes. For instance approximately 10% of the Maine population will experience SAD while only 1% in Florida.
Shiftworkers who already experience a loss of light exposure due to their jobs may be even more affected. Consider the night worker who must sleep through a large portion of the day, only to wake up to a dusky evening before getting ready to go to work.
Scientists believe that SAD is related to the biological clock, and that our old friend melatonin is highly responsible for the development of SAD. In other words, when we get too much of it, we get more depressed. And the reason we get too much melatonin, is that … once again … (you should know this by now) … less light means the pineal gland secretes more melatonin (which is supposed to make us sleepy). In fact, one of the classic symptoms of SAD is sleepiness and lack of energy.
Some of the other symptoms of SAD are:
1. Intense cravings for carbohydrates and sweet, usually resulting in weight gain.
2. At least one major depressive episode each winter with feelings of extreme hopelessness and failure.
3. Difficulty in focusing and concentrating on work.
4. Heavy feeling in the arms and legs
5. Irritability
6. Withdrawal from social situations
7. Loss of interest in activities you once enjoyed
Doctors also believe that serotonin and changes in the brain cortex may be involved in SAD, but the effectiveness of light therapy and the resulting changes in the production of melatonin strongly suggest a fundamental relationship between SAD and melatonin (and the workings of the biological clock and circadian system.) They also find much more melatonin in patients suffering from SAD.
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