New Internationalist

A Shot In The Arm

Issue 132

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MENTAL HEALTH [image, unknown] Placebos

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A shot in the arm
Placebos are medical treatments with no active ingredients.
There is no physical reason why they should work. But they do.
Phil Richardson explains why.

How would you feel if you found out that the pills your doctor prescribed were made of sugar, your injection just sterile water, your tonic a bottle of harmless coloured liquid? Embarassed, probably. Or angry that your complaints were not being taken seriously. But if you didn’t find out, you might find yourself feeling rather better.

Placebos - as such bogus treatments are called - have been shown to have powerful effects in relieving most known medical conditions.

For some people an injection of water may relieve their pain just as effectively as morphine. And fake surgery - where a patient is given an operation scar without having anything else done - has been found to produce dramatic improvements in patients with heart disease, reducing their attacks of angina as well as the level of drug dosage they need. What experiments like this show is that even genuine treatment works only partly through its physical effect. Placebo power does the rest.

This is especially so in psychiatry where it has been calculated that at least 40 per cent of the effect of psychoactive drugs (tranquilisers, antidepressants and so on) is due to their placebo effect. Even the drug companies marketing psychoactive agents have found it hard to demonstrate that their drugs’ therapeutic effects are greater than those of a well-administered placebo.

When tricyclic antidepressants (such as amitryptaline, the drug most widely prescribed by doctors for depression) are compared with placebos that give the patient a dry mouth - a common side effect of tricyclics - six out of seven studies found the placebo just as powerful as the antidepressant. Giving people a dry mouth made them believe that something was happening and they immediately felt less depressed.

In another study simply being admitted to hospital made 30 per cent of depressed people feel better. Admission to hospital plus a placebo antidepressant made 50 per cent feel better. Admission, placebo, and electroconvulsive therapy made 70 per cent feel better.

Just as not everyone can be hypnotised, so only a proportion - albeit a large one - will derive benefit from a placebo. Estimates range between 20 to 80 per cent. And, not surprisingly, people with anxiety or depression are the most likely to experience placebo power, with at least 50 per cent being helped by the bogus pills.

Placebos work because patients believe they will. Their faith in the treatment - or, more likely, their faith in the doctor prescribing the treatment - makes them expect to feel better. And - lo and behold - they do. So why doesn’t everyone respond dramatically to sugar pills and coloured water? Commonsense would have us believe that the responders must differ from the non-responders in some important way. They must be more suggestible or more gulible - or more something. Indeed researchers have made numerous attempts to identify the personality characteristics of the so called Preactor. But virtually all such attempts have failed. People who derive benefit from placebos turn out to be no more suggestible in general than anyone else. In the rare instances where some differences have emerged from such personality studies they are usually contradictory. For example, one group of investigators found extroverts to be the strongest P-reactors whilst another showed that it was the more introverted patients who gave strongest response.

Investigations of this sort are based on the seemingly logical premise that the P-reactor exists; in the other words that people will consistently respond to sugar pills - or consistently not do so. But in one fairly typical study child-bearing women were offered a placebo both during labour and afterwards to relieve their post-partum pain. It was quite impossible to predict from the first occasion who would get pain relief on the second.

More important than the personality of the patient seems to be style of the placebo. Bogus injections, for example, tend to have stronger effects than bogus pills. And false surgery may be more powerful still. The colour, size and apparent dosage level of a pill also seems to be important - with green working better for anxiety and yellow more effective for depression!

And any treatment that seems scientifically sophisticated tends to be especially powerful. X-rays are a good example. Patients often thank their radiographer for the ‘treatment’ which made them feel so much better - even though the treatment was nothing more than a diagnostic photograph.

But over and above the importance of the type of placebo used is the style of the person administering it. Status and confidence are crucial. Doctors are better than nurses. And doctors who seem to have confidence in the placebo can instil similar confidence in their patients.

The power of the doctor is demonstrated by a remarkable experiment carried out at John Hopkins University in the US. Fifteen patients with anxiety were given placebos, along with the following instructions: ‘Many people with your conditions have, been helped by ‘sugar pills’ and we feel that such a pill may help you too. A sugar pill is a pill with no medicine in it at all. Are you willing to try it?’. Fourteen of the patients took the pills and all but one showed clear improvement. In other words, so powerful is the faith in the doctor, even when people know they’re being given a placebo, they feel better.

This indicates the placebo may gain its major effect as a symbol of the healing power of the doctor. When we carry a bottle of pills in our pocket or handbag perhaps we are really carrying the doctor around with us. Recently this idea has been extended by a group of US entrepreneurs who are now marketing a ‘placebo medallion’. The wearer is invited to put faith in it in order to receive all the benefits that normally accrue to recipients of placebos.

From one point of view this looks like a piece of cynical commercial exploitation - of the sick and vulnerable. From another perspective however, the idea of a placebo medallion brings us one step closer to a solution of the paradox of placebos: by believing in their doctors patients can cure themselves.

It is the belief of the patient that counts. All the apparent placebo power of the doctor dwindles to nothing if the patient chooses not to believe. Ultimately, then, placebo power resides within the patient - not the doctor. If as patients we are prepared to recognise this fact then we can take greater responsibility for our health and well-being.

Phil Richardson is Lecturer in Psychology at St. Thomas’s Hospital in London.


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