On a cold, dark January day, your brain just slips into neutral. Thoughts crawl along like a snail on sedatives, you can barely remember your own name, and higher functions like mathematics are simply beyond your ability. Right?
Not according to a recent study. Apparently, our minds are actually sharper in the winter than in the summer!
Like you, psychiatrists who study seasonal affective disorder (SAD), a.k.a. the “winter blues,” have always assumed mental processes slow in the cold and dark of winter. But last year Tim Brennen, a psychologist at the University of Tromsø, Norway–the most northerly university in the world, 300 kilometres north of the Arctic Circle–decided to test the idea.
Brennen gave 100 residents of the community five standard tests for attention lapses, impaired memory and slow or foggy thinking, once in December, and again in June. To his surprise, people’s scores were better in the winter than they were in the summer on four of the tests.
This is encouraging some people who research SAD, because it could mean that SAD sufferers are at least capable of thinking and reacting normally and aren’t more likely to be involved in traffic accidents or otherwise endanger themselves or others.
Other researchers, however, point out that Brennen didn’t actually study people who suffer from SAD, whom they think might exhibit mental changes the rest of the population doesn’t. That study remains to be done.
SAD is diagnosed in someone suffers three or more consecutive winters of some (or all) of: sleep problems (usually difficulty staying awake, but sometimes difficulty getting a sound sleep or waking up too early), lethargy, overeating (caused by a craving for carbohydrates), depression, social problems (i.e., irritability and a desire to avoid people), anxiety, decreased interest in sex and, sometimes, mood swings and, in the spring or autumn, three or four weeks of excessive activity. Most people suffering with SAD also show signs of a weakened immune system in the winter, which makes them more vulnerable to illnesses.
SAD can crop up in people of any age, but it’s most common in people between 20 and 40. It tends to run in families, and affects three times as many women as men. It becomes more common the further north you go: the Harvard Mental Health Letters identifies Fairbanks, Alaska, as the place with the most SAD sufferers, a full nine percent of the population. But even as far south as Maryland, more than 90 percent of people interviewed report at least some of the symptoms.
SAD is more common further north because it appears to be caused by a lack of bright light. Research has shown that it can usually be alleviated by exposing the sufferer to an amount of light similar to what he or she would receive during the summer.
This “light therapy” consists of sitting less than a metre away from a specially designed “light box” that allows bright light–at least 10 times as bright as ordinary domestic lighting–to shine directly into your eyes. It’s not necessary to stare directly into the lights; just sitting there reading or doing something else and occasionally glancing up is enough to garner the benefits. In one study, 40 to 60 percent of SAD patients improved after sitting next to a light box for just half an hour a day.
A light box, alas, isn’t something you can whip up in your own workshop. Too little light does no good, too much can cause eye damage, and the precise amount of time needed in front of the light box varies greatly from person to person and changes as the seasons progress. Some SAD sufferers have to combine light box therapy with psychotherapy and anti-depressant drugs such as Prozac and Zoloft to get results.
Light affects the release of a hormone called melatonin by the pineal gland. The retinas of people who suffer from SAD appear to be less sensitive to light during the winter months, which could result in an over-production of melatonin. A study in the journal Arctic Medical Research indicates that people with a high level of melatonin in their blood during the day are more likely to have SAD than other people, supporting this notion.
If you suffer from SAD, see your doctor; help is available. If you don’t suffer from SAD, then it appears that for the rest of 2000, you’ll never be as mentally sharp as you are right now.
Ugh. Now I’m really depressed.
