A depressed mood is common among people in northern latitudes in the winter. It was first described as early as the 6th century by Goth historian Jordanes. In his Getica, he describes it in reference to the people of Scandza, an early term for Scandinavia. The formal modern appellation and description of SAD was developed in 1984 by Norman E Rosenthal and colleagues at the American National Institute of Mental Health. Subsyndromal Seasonal Affective Disorder is a milder form of SAD experienced by even more people. Cats, however, don’t go in for clinical reading and don’t try to put a label on things the way we humans do. Cats don’t suffer from SAD. Are they lucky or smart? Let’s consider.
The precise cause of SAD remains unknown and there have been a range of factors considered to contribute. Many studies have been done with sometimes contradictory findings. However, it is generally agreed that women are affected two to four times more than men, depending on who you read, and younger people are more affected than older people. One mechanism for the developing of SAD in some people may be a difference in the way they produce melatonin. Melatonin is produced in dim light and darkness by the pineal gland in the brain. Studies have shown women in general and men diagnosed with SAD secreted melatonin for longer periods during winter nights than during summer nights. The decrease in light also can disrupt circadian rhythms and lead to a decrease in serotonin, another brain chemical that stabilizes mood.
Depression is a serious condition and should not be ignored and serious SAD falls into that category. But before reaching for the prescription pad we might consider some things. Nature wants us to change our pace in winter, to slow down and rest. For many, if not most animals in nature, is is a time scarce food, deep cold and reduced sunlight. Some species respond by entering a deep hibernation. Most exhibit reduced activity. While your cat is living in modern society with you he or she will still show signs of adapting to winter. Humans, on the other hand, do not allow themselves this slowdown and adaptation. Even if they would, the structure of modern life does not permit it.
During most of human prehistory food was scarce in winter for people too, and cold and snow made activity difficult for them as well. Interestingly, the Mayo Clinic lists as symptoms of fall and winter SAD oversleeping, craving for foods high in carbohydrates and weight gain. For our Ice Age ancestors, putting on weight with carbohydrate rich foods and longer sleep cycles would have enhanced their chances of survival. They would have required far fewer calories. Compared to them we might as well be living on another planet. We live an existence which denies the seasons and ignores biology. Even right up until the industrial revolution life slowed down in winter and almost everyone would transition into a winter pattern of longer nightly sleep and reasonable weight gain. Today, however, SAD sufferers, even more than those not affected must force themselves to operate on what is in effect a year-round summer pattern.
Since your cat sleeps so much anyway, you may not notice a change in sleep pattern. But decreasing light also triggers the growth of a winter coat. Even in my indoor only cats I see the coats thicken and lengthen. But the cats don’t give up entirely on activity in winter, either. They still want to play with their toys and have me flash the laser dot around. Like Even as the Ice Agers needed to continue hunting, gathering firewood and collecting water, the cats still want exercise. Fits of wild running through the house are far more common in winter and tend to happen more when I neglect the laser. Exercise has proven to help SAD. The cats also spend a lot of time in the windows. Sunlight helps SAD sufferers and there are light boxes to provide it artificially if needed, but getting outside for some exercise on sunny days helps two ways..
Interestingly, Iceland is an exception to what is usually found in SAD observations. A study of more than 2000 people there found the prevalence of SAD and seasonal depression to be unexpectedly low in both sexes. At first thought to be a genetic tendency in a highly related population, it is now believed to be attributed to the large amount of fish traditionally eaten by Icelandic people, almost four times as much as Americans. This is corroborated by similar findings in Japan, where fish consumption is triple that of America. Needless to say, fish and fish products are a big part of your cat’s diet.
Emulating your cat and adapting to the seasons may not keep SAD away from your door. If it does affect you, remember cats also don’t bother with guilt. If you are more sleepy, don’t let people who carry on like Energizer bunnies make you feel useless. Make sure you get a good night’s sleep and take naps if you need to. Naps are socially acceptable in enlightened circles these days. If you crave carbohydrates and gain weight, just make sure they are healthy carbs and remind your self it will be much easier to get the weight off in the spring when nature intended. Remember, taking criticism to heart and guilt are also a sure path to depression. Cats nearly always ignore criticism and criticism of something innate to your biology should be treated like a cat would.