The author is a Toronto-based freelance writer.

Over the past few years, Rosemary Renton has diagnosed her own infections and rashes. She's figured out how to treat her little boy's eczema. She's analyzed his stool. When her friends come to her with symptoms, she tells them what's wrong.

Renton isn't a doctor. Not even close — she's a school librarian in Barrie, Ont.

But Renton knows her way around a computer mouse, and says she's mastered the art of online medical fact-finding. "I diagnose myself all the time. I'm always right."

Well, almost always.

Even a web M.D. can have an off day. When Renton was pregnant and a doctor said her blood pressure was seriously spiking, she spent hours glued to her computer screen, researching the symptom — and sobbing because she thought her days were numbered.

"It absolutely devastated me," she admits. "I didn't realize that blood pressure can be huge when you're pregnant. You really can die from it, and your baby can die."

It turned out all was well. But Renton agrees that it's easy to get carried away when you're armed with a modem and an imagination.

"You start planning your own funeral," she chuckles.

"Information is one thing, and knowledge and perspective is another," notes Larry Reynolds, a family physician in Winnipeg who sees more and more patients coming into his office with printouts. "Sometimes you can be too close to your own symptoms. And if you don't have training as a health care provider, you don't have a sense of what's common and what's rare."

Well over half of online Canadians — 58 per cent — search the internet for health information from home, up from 46 per cent five years ago, according to Statistics Canada.

Part of that rise may be due to the fact that these days, it's a long wait to see a medical specialist. Five million of us don't even have access to a family physician. By using the internet, we can instantly get our hands on medical information, symptom checklists, discussion groups, even pseudo-scientific studies and cure-all products.

"There's a huge volume of information," says Ellen Balka, principal investigator of Action for Health, a B.C. research group that studies how Canadians use online health data.

While it would be nice to think that we're mostly sussing out the benefits of Pilates or the best sources of vitamin D, that isn't happening. Balka says it seems most of us are checking symptoms and looking up treatments.

"We tend to go online after health crises," she says.

So many folks are now Googling their aches and pains that this group has been dubbed cyberchondriacs.

"Patients have always looked at medical textbooks," says Reynolds. "Everybody tries to diagnose their problem. That's just part of being human."

The internet just cranks it up by offering easy access to huge volumes of information.

Mary, a health educator who'd rather not 'fess up to her last name, says she constantly investigates her symptoms online. "I've been a hypochondriac for many years," she admits.

When she fell in love, Mary researched her heart palpitations. When she suddenly started having migraines, she looked up brain tumours. "

"Most of the time I live under the understanding that I'm dying, I just haven't been diagnosed," she adds wryly.

"Checking the internet is a means of seeking reassurance," explains Gordon Asmundson, a University of Regina psychologist and co-author of It's Not All in Your Head: How Worrying about Your Health Could Be Making You Sick — And What You Can Do About It. "For some people, they check everything, and they need to check it excessively."

Unfortunately, he says, medical websites often provide anything but reassurance. "They expose a person to a lot of alarming information about rare and lethal conditions. So people get trapped in this cycle."

Mary calls online checking a "fix" and says it only feeds her paranoia. "Ninety-nine per cent of me knows it's in my head. But one per cent says maybe I do have cancer."

Most of the time, suffering anxiety about a nonexistent medical condition is about the worst that can happen to the middling cyberchondriac. That is, until she's tempted to actually treat the self-diagnosis.

"Now you can buy pharmaceuticals and other things on the web without prescriptions. That can lead to unfortunate effects," points out Asmundson.

And once in a while, a self-diagnosis can shroud something more serious. If you shrug off the symptoms of bowel cancer as nothing but hemorrhoids after researching it on the internet, you may be postponing the medical attention you urgently need.

The bottom line: click responsibly.

"Overall, the internet is an enormous potential benefit for doctors and patients," says Reynolds. "It means doctors can access the most up-to-date information when treating patients. And I can't think of a doctor who doesn't want a well-informed patient."

So how to do it right?

"Go to a library. Spend some time with a health librarian who can provide support," says Balka. "Most of us need help figuring out what is relevant. That assistance can range from finding more appropriate ways to conduct searches, to assessing the quality of information available."

Or you can simply copy Renton's new strategy. When she wants to check serious symptoms — the ones she's convinced are a harbinger of some fatal disease — she puts her husband in front of the computer.

"I tell him what to Google, and have him read the prognosis and get back to me," she says.

Renton, meanwhile, waits in the next room. Where there's no high-speed connection.

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