For decades, doctors have known of a simple pill which has virtually no side effects, costs hardly anything to produce, and cures or improves a wide range of illnesses for large numbers of people. Yet it cannot be bought over the counter and doctors cannot prescribe it, except in carefully controlled trials. Why?
The seemingly miraculous tablet is a fake medicine, a totally inert sugar or starch pill, designed only to deceive us into believing we are receiving a genuine treatment. Dummy medicines - called placebos - are used in clinical trials to test a drug or other remedy against an inactive control. They are given out randomly, with neither patients nor doctors knowing who receives the active medicine. Yet fake remedies work so well in many trials that researchers are now beginning to explore how this powerful force might be harnessed to improve mainstream medicine.
The 'placebo effect' has mystified doctors for years. Numerous studies have shown that fake pills, dummy therapies, and even simulated surgery, work as well as the genuine article for many illnesses. A landmark report in the US in 1955 found that one in three people will recover from a range of conditions simply through taking placebos.
Fake surgery has been shown to help angina, Parkinson's disease and arthritis. In June, doctors in Houston reported in the New England Journal of Medicine that patients with arthritis of the knee were successfully treated just as well with pretend surgery - just small incisions into the knee - as with one of the most common operations for the condition.
Fake psychotherapy, pretend acupuncture and sham injections are all remarkable success stories, too. Placebo medicines have proved to be wonder drugs for pain relief, asthma, depression and the common cold. And placebo complementary therapies, from fake Ginkgo biloba to dummy homeopathic potions, also appear to work as well as their genuine equivalents. Indeed, many sceptics believe complementary medicines only work through a placebo response.
Showing well-established therapies to be no more effective than dummy remedies is not always a popular finding. And although placebos can be effective, doctors cannot ethically prescribe patients a fake tablet without their consent.
'At the moment, there is no place for it,' says a spokeswoman for the British Medical Association. 'If you are not being honest with the patient, it is unethical. You must say what this drug is doing. Once people know it is a placebo, it would not have an effect.'
But Professor Jos Kleijnen, director of the NHS Centre for Reviews and Dissemination, is convinced that the placebo effect holds vital secrets which could be applied to general healthcare.
'This is a very important area which potentially has a lot of promise,' he says. Professor Kleijnen dismisses recent research published in the New England Journal of Medicine last year, casting doubt on placebos. Danish researchers analysed more than 100 trials where placebos were tested against both genuine therapies and against no treatment. They concluded that placebos did not perform significantly better than doing nothing - in other words, patients simply get better without any treatment because illnesses go away or fluctuate from day to day. Only in pain relief could they discern a definite effect. Yet similar wide-ranging studies have shown demonstrable placebo responses, argues Kleijnen. 'I believe there is a real effect,' he says.
Like most scientists, he believes the placebo response is an act of faith. Patients unknowingly given fake medicines get better because they believe they will. But exactly what prompts such belief in our medical system, and how this faith converts into a healing power, remains a rich seam for investigation.
Kleijnen believes that the relationship between patient and practitioner, and the context of their meeting, are key. Potent symbols in the consulting room, from the medical equipment to the ritual of treatment, all prompt expectations in patients that they will get better. The more impressive the remedy - such as the arthroscopic knee surgery and fake acupuncture - the more dramatic appears to be the effect. Illnesses with a psychological or psychosomatic element - such as depression or asthma - appear most susceptible to the power of faith. At the same time, the practitioner's empathy is crucial. 'If you see a doctor who pays attention and makes the patient feel he or she is taken seriously, that has positive effects as well,' he says.
Complementary therapists often seem better than mainstream medics at providing this caring relationship, he points out. A homeopath may spend up to two hours with one patient, attentively listening to all their concerns, while a rushed GP has six minutes to probe a specific ailment. Kleijnen believes it is this tender loving care, rather than anything in the therapies, which explains the apparent success of homeopathy and other complementary remedies. But whether this combination makes us simply feel better - without any biological change - or somehow triggers healing mechanisms in the body which actually make us better, is the subject of fierce debate.
Professor Tony Moffatt, chief scientist of the Royal Pharmaceutical Society, is adamant we are fooling ourselves. 'There is no doubt it is a powerful effect,' he says. 'If someone believes something is going to do them good, the chances are it will. Nothing is happening to the body.' A placebo treatment cannot fight the virus which gives us flu, he says, but it may still make us feel better.
Other scientists point to research which suggests a more direct relationship between mind and body. Psychoneuroimmunology shows that impulses in the brain can trigger changes in the immune system. Research on anti-depressants has thrown new light on these theories.
Scientists in Texas found that brain scans showed the same altered patterns in patients on placebos as those on Prozac, although the Prozac patients also had additional brain changes suggesting that brain impulses leading to recovery can be triggered by a medical relationship as much as a pill.
Professor Helen Mayberg, who led the research, says: 'Our findings are consistent with the well-recognised placebo phenomenon that expectation that a treatment will be helpful is a critical part of the therapeutic relationship between a patient and their doctor.'
At an NHS hospital in Scotland, Dr David Reilly, consultant physician at the Glasgow Homeopathic Hospital, is using new understanding about the placebo effect to improve practices in his own hospital and help doctors create more therapeutic consultations.
Reilly, a physician and GP who also practises homeopathy, believes we all have innate healing powers. The placebo effect is simply an example of the body healing itself triggered by expectations, the environment and our cultural experiences. Different coloured tablets, or a room with a view, can all make a difference to how we respond to treatment, he says.
Reilly already applies knowledge of the placebo response in his own practice, which offers both orthodox and complementary therapies. Interior designers are working on a 'therapeutic environment' and, in stark contrast to a typically austere and grubby NHS hospital, the award-winning redesign emphasises beauty and harmony in order to help patients feel relaxed and safe even before they meet a doctor. In appointments, staff consciously use empathy to bolster treatment.
But Reilly is also now teaching orthodox doctors how to take a more holistic approach in consultations to draw on the placebo effect. In courses for Scottish GPs, he helps doctors listen more effectively, empathise with patients and 'tune into' patients' experiences. The approach has nothing to do with modern communication techniques - 'You cannot bullshit it,' he says. Instead, he encourages doctors to use old-fashioned notions of 'human caring' to help patients heal themselves.
Although he admits that longer consultations would help, he believes the human factor is even more vital, given only short appointments. It takes only 15 seconds to make an asthma attack better or worse through fear or mistrust.
'The central core issue,' says Reilly, 'is how we can effect a better healing response in our patients.'