The Truth About Seasonal Affective Disorder
A lot of us go into hibernation mode every time the cold comes around, socializing less and feeling like we only have enough energy for binge-watching TV shows. But for the 15 per cent of Canadians who suffer from seasonal affective disorder (SAD)—depression that occurs every year, most often in the darker months—it goes beyond that. They oversleep, overeat, and feel guilty, irritable and hopeless. The symptoms usually come on in the fall, peak in late January, and go away in the spring.
About three per cent of Canadians acquire a more severe form of SAD, which can have a devastating impact. But while the condition is now widely known, we still don’t know exactly what causes it. The prevailing theory is that long winter nights throw off your circadian rhythm—the internal clock that regulates when you feel sleepy and when you’re alert. “As the days get very short, some people have difficulty adapting to that change, and the body’s rhythm is thrown out of sync,” says Robert Levitan, a psychiatrist at the Centre for Addiction and Mental Health and professor of psychiatry at the University of Toronto. That would explain why people who live closer to the equator, where the days are the same length year-round, are much less likely to acquire SAD; only one per cent of people living in Florida have it, for instance.
Another hypothesis is that the lack of sun changes your brain activity. If you don’t get enough light, your body produces fewer neurotransmitters like serotonin, which helps keep your mood stable, and too much melatonin, the hormone that makes you feel sleepy. SAD may also be hereditary; having a relative with the condition increases your chances of getting it by up to 17 per cent. And a University of Iceland study that screened Winnipeggers for SAD found that those with Icelandic genes were significantly less likely to have the disorder, suggesting that people whose ancestors are from climates with less sun may have built-in resistance.
There is light at the end of the tunnel—and not just spring. For people who suffer from SAD—and really, for anyone made grumpy by 4:30 p.m. sunsets—a combination of lifestyle changes and doctor-recommended treatments can reduce symptoms and provide lasting relief. Read on to find out.