A few weeks ago, I was feeling under the weather. After days of feverish internet diagnosis, I finally dragged myself off to the doctor. Unfortunately, after examining me, she feared the worst too. Concerned that my heart rate was fast, she handed me a sealed envelope and sent me off to A&E.

Did I go straight there? Did I heck. Instead, I rushed home and did what any right-thinking person would do: I logged on to Google. Knowledge is power, right? If I was dying, I would need to put my Jude Law Hamlet tickets on eBay. Alas, the problem with Dr Google is he isn’t exactly a comfort in times of crisis.

For future reference, if you find yourself with an irresistible urge to type in supraventricular tachycardia, don’t — just don’t. Wrongdiagnosis.com wasn’t much better, scaring me with a list of 407 possible causes of palpitations. I raced to the hospital, convinced I was a candidate for open-heart surgery.

Fast-forward four hours — during which time I died a thousand deaths — only to find out I had a chest infection... and a bad case of cyberchondria. The only consolation for the latter condition is that I’m in good company. A Microsoft survey of 1m internet users last year found that 2% of all searches were health-related and a quarter of all participants engaged in at least one medical search during the study.

Unfortunately, once it has taken hold, cyberchondria can be hard to cure. Since my trip to hospital, I have been obsessively checking my pulse, lurking in chatrooms and swotting up on worst-case scenarios. What if the doctors got it wrong? What if the ECG machine was faulty? After all, how often are they serviced? It’s exhausting, convincing yourself you might have a life-threatening illness. “People with cyberchondria and hypochondria, or health anxiety, as it’s more sympathetically known, often let their imagination get carried away and misinterpret their symptoms,” says Elaine Iljon Foreman, a psychologist specialising in anxiety disorders. “Obviously, if you have physical symptoms, you should get them checked out by a doctor before assuming they are caused by anxiety. There’s an old joke about the tombstone marked, ‘I told you I was ill.’” Patients showing signs of cyberchondria are treated with a programme of cognitive behavioural therapy, which often involves restricting access to health websites.

For some people, cyberchondria can be highly damaging. “I had one patient who was so convinced she was going to die early, it was destroying her quality of life,” says Iljon Foreman. “She wouldn’t go for promotion, because what was the point, since she was going to die. She wouldn’t form new relationships and she found it difficult to enjoy good times with her children on holidays and at birthday parties without being overwhelmed with sadness that this could be the last birthday, the last holiday. After therapy, she was able to rebuild her life and now has a new job, a new boyfriend and a happy family.”

“There is no question that we’re facing an epidemic of cyberchondria,” says Dr Sarah Jarvis, a GP and author of Women’s Health for Life. “These people are in the same position I was when I started out as a medical student. It took me six years of learning about all the ghastly stuff before I realised that common things occur commonly, and rare things are rare. Websites are duty-bound to take you through all of the possibilities — so a headache might be meningitis or a brain tumour. I can often tell by looking at someone from the opposite end of the waiting room that they have meningitis — no website can do that.”

Jarvis points out that misinformation and miracle cures are particularly prevalent when it comes to women’s health issues, such as cervical cancer, breast cancer and pregnancy. “Nobody ever reads a website and is reassured. They have to list every eventuality, and that usually includes the information that you’re dying.”

This issue was highlighted by the Microsoft study, which revealed that one in four of all articles thrown up by an internet search for “headache” suggested a brain tumour as a possible cause, despite the fact that they develop in fewer than one in 50,000 people. People also associate prominent search positions with probability, so if you type in “mouth ulcer” and see “mouth cancer” with several mentions near the top, you think that it must be very common, which is not the case at all.

Another vexing problem for cyberchondriacs is the accuracy of online information. “Once something has been put up on the internet, even if it’s wrong, it’s difficult to remove,” says Jarvis. “This is particularly true of scare stories, and also of alternative remedies claiming to be miracle cures.” A recent American study by Pew Internet revealed that, while eight in 10 of us use the internet to look up information about our health, nearly the same proportion — 75% — do not check the source of that information or the date it was created. Check the facts? I’d love to, but I’m off to buy a heart-rate monitor, and then I really must Google “cyberchondria”.

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