While the Internet can make us into instant experts on our health, a new report suggests that a little knowledge can be a dangerous thing. Health correspondent Barry Nelson reports.

PATIENTS using the Internet to find out information about chronic disease rather than listening to their doctor could be putting their health at risk, according to researchers. Using interactive computer tools, such as online support groups and chatrooms, does help improve the knowledge of people with conditions such as asthma and diabetes and provides positive feelings of social support. But researchers from University College London have come to the conclusion that there was no evidence that ''cyber medicine'' helped people change their behaviour.

They even say there is evidence that using interactive services may actually leave patients in worse health.

The team, led by Dr Elizabeth Murray from the Department of Primary Care and Population Sciences, reviewed 28 trials involving more than 4,000 participants to measure the effectiveness of Interactive Health Communication Applications (IHCAs).

These were defined as a computer-based information sources combined with one or more additional services, such as online support groups, chatrooms or tailored advice based on data provided by the user.

The researchers found that the IHCAs had a positive effect on people gaining information and feelings of social support. But they concluded that the applications had no effect on making patients believe that changing their behaviour for the better was possible or in actually resulting in behaviour change.

They also said that they had a ''strikingly negative effect'' on health outcomes, leaving some in worse health.

Dr Murray says there were a number of reasons why there was an apparent contradiction between actively seeking knowledge and patients' seemingly worse health. One reason was that when patients learn of small but important statistical effects of their treatment, they become less frightened.

This would leave them less motivated to change the way they behaved than if a doctor bluntly told a diabetic to control their sugar level or face death, for example. ''But actually, if you become more knowledgeable you realise it's all rather a long way off,'' says Dr Murray. ''They are less frightened and that reduces their motivation to be really strict in their control.''

Dr Murray also believes that ''knowledge-seekers'' might become ''so steeped in information'' from the Internet that they make their own treatment decisions, contradicting advice from doctors.

This might mean that a diabetic who was told by their doctor to lower their blood sugar levels might decide, based on their interpretation of the data, that the short-term trade-off of not complying was worth the long-term risks. Dr Murray says: ''We found that people who use these things (IHCAs) had more sugar in their blood than those who didn't.''

Many patients find comfort by discussing their condition with others who have the same illness. But Dr Murray says that some researchers ''worry that the friends you make on the computer are not the right sort of friends, won't be there for you and may not be good for your social well-being''.

The researchers warn in the journal Cochrane Collaboration: ''If knowledge was all that was needed to promote healthy behaviour, smoking would not be as prevalent as it is.'' They also suggest that well-informed patients may not drive down healthcare costs, but could increase them by demanding specific or more costly treatments.

Dr John Canning, a GP at the busy Endeavour practice in Middlesbrough, believes that common sense and "healthy scepticism" are essential when navigating the Internet. "A lot of websites are very good and provide accurate, up-to-date information for patients but there are others which can be very misleading," says Dr Canning, who sits on the national GP committee of the British Medical Association.

He admits that "worried, well" patients brandishing sheaves of paper printed off from the Internet are not very numerous at his own practice.

"I suspect it is doctors in more affluent areas who tend to get more people coming in with queries generated by the Internet but we certainly see patients who have looked up information on the net," he says.

One of the problems with much of the information on the net is that it is either irrelevant, unreliable or out of date, the GP says. "I would encourage people to find out more about their problems and our practice staff can often point people in the right direction. But there is an awful lot of rubbish out there and you have to be careful." Patients at the Endeavour practice who ask for guidance about where to look on the Internet are often advised to go to a trusted website called www.prodigy.nhs.uk.

Set up by a multidisciplinary team based at the Sowerby Centre for Health Informatics at Newcastle University, the website aims to provide doctors with the most up-to-date medical information and guide patients to reliable sources of information about common conditions.

One popular area of this NHS-approved website concerns patient information leaflets. By clicking on this part of the website, patients can choose from a wide variety of approved, reliable sources of information.

The leaflets are specifically designed to be easily readable and understandable by people who are not healthcare professionals.

Ian Purves, professor of health informatics at Newcastle University, says the website dates back to the mid 1990s and was originally designed to help GPs keep in touch the latest medical developments. "It's said that every doctor needs to read 16,000 journal articles a year to keep up to date. We try to distil that information for them," says Prof Purves. "At any one time we have about 10,000 people logged on and a couple of hundred thousand people a month use our website."

Information aimed at patients is deliberately kept simple, recognising that the average UK reading age is just 12.

Katherine Murphy, from the Patients Association, says: ''The problem with getting information from the Internet is that it's not always accurate.

''There is always the danger that someone searching the Internet will find they have miraculously found a cure for a condition when they actually haven't.''

Ms Murphy says there is the potential for information picked up from the Internet to cause conflict between patients and doctors. ''They might go to their doctor asking for X, Y and Z armed with information off the Internet but this might conflict with what the doctor is telling them they should be doing.''

But she says that the Internet is very good for much information for patients, so long as it is from a reliable source.

Dr Canning believes that most people in the North-East have enough common sense to navigate their way through the maze of information in cyberspace. "People need to be careful but I think this report is probably a bit too sceptical about the benefits of using the Internet," he says.

* Prodigy can be accessed by going to www.prodigy.nhs.uk