The Placebo Effect

"It's not a lie if you believe it" - George Costanza from Seinfeld

In his book "Six Easy Pieces", the late Nobel Prize winning physicist Richard Feynman wrote:

" ... psychoanalysis is not a science: it is at best a medical process, and perhaps even more like witch-doctoring. It has a theory as to what causes disease - lots of different 'spirits,' etc. The witch doctor has a theory that a disease like malaria is caused by a spirit which comes into the air; it is not cured by shaking a snake over it, but quinine does help malaria. So, if you are sick, I would advise that you go to the witch doctor because he is the man in the tribe who knows the most about the disease; on the other hand, his knowledge is not science. Psychoanalysis has not been checked carefully by experiment, and there is no way to find a list of the number of cases in which it works, the number of cases in which it does not work ..."

He was writing about psychoanalysis. Psychoanalysis has been called "quackery" and "pseudoscience" and, as Richard Feynman suggests, it has little or no scientific basis; yet it has been successful in helping a lot of people to overcome debilitating mental issues. How is it that it works? It has been suggested that the success of psychoanalysis can be attributed to the placebo effect.

The word "placebo" is Latin for "I will please", and has come to refer to a treatment or substance which is pharmacologically inert (such as a sugar pill) but which may produce therapeutic benefits based only on the power of suggestion; the mind can heal. The opposite of this is "nocebo" - Latin for "I will harm" - where a substance may cause harm based only on the power of suggestion; the mind can incite both physical and mental illness.
The late Arthur Shapiro was a professor of psychiatry at the Mount Sinai School of Medicine in New York, and an expert on the placebo effect. In an essay that he co-wrote in 1995, he wrote: "until recently, the history of medical treatment is essentially the history of the placebo effect". He was suggesting that, before the advent of modern medicine, almost all of the myriads of remedies were placebos. Shapiro also noted that patients tend to respond better to new drugs than to older, more established drugs. He argued that a brand new wonder drug draws high expectations on the part of the patients and doctors, and these expectations can become self-fulfilling.
An example of a placebo cure was a cure-all called theriac, which consisted of a large number of ingredients, including opium, hemp and viper flesh. Greek physician Galen was probably the first to describe this medicine, and one of his patients, Roman Emperor Marcus Aurelius, took it regularly. Galen himself realized that the most important ingredients of such remedies is faith - the patients' belief that the treatment will work. Galen wrote: "He cures most successfully in whom the people have the most confidence".
There are modern examples of confirmed cases of the placebo effect in action.
In 1950 in a New York hospital, a group of pregnant women were given a drug by Dr. Stewart Wolf, and told that it would cure them of persistent nausea and vomiting. Sure enough the drug worked like a charm (so to speak) - the women were nausea-free and the only thing that spewed from their mouths were cries of joy. The problem was that the drug they were given was syrup of ipecac which is used to induce vomiting. Thanks to the placebo effect, it actually had the opposite effect.

One of the most incredible examples in the history of medical science is the so-called "mammary artery ligation" procedure which was used by cardiac surgeons to relieve the pain of angina. This involved making incisions in the patient's chest and tying off their mammary arteries (these are arteries just below the ribs). The idea was that if the blood flow through these "superfluous" arteries was stopped, there would be more blood available to flow to the heart and, bingo!, no more pain. The operation had a high success rate over a few decades, with many happy customers reporting improvements. However, it was later found that an even higher success rate was attained by receiving only a simple incision without tying off any arteries, and nothing more. Behold the power of the placebo effect.

This powerful placebo effect is probably one big factor in the diffusion of remedies of questionable efficacy, such as faith healing, homeopathy, new-age holistic healing, vitamins, acupuncture, magnetic pain-relief bracelets and alternative medicines. As mentioned earlier, it has been suggested that psychoanalysis is nothing more than a placebo; in fact, psychoanalysts can enhance their effectiveness by appearing authoritative and knowledgeable - for example, by having their impressive-looking medical degrees and qualifications on display in their consulting rooms.

So how does this placebo effect actually work? Some people have tried to explain it by invoking the concept of classical conditioning. At the turn of the 1900s, Ivan Pavlov, a Russian physiologist who experimented with animal behaviour, discovered classical conditioning when an animal learns to associate 2 events - one neutral (the conditioning stimulus) and the other meaningful (the unconditioned stimulus). The animal learns to respond to the normal event even in the absence of the meaningful event. In Pavlov's most famous experiment, a bell was rung just before a piece of meat was given to a dog. At first, the dog did not salivate until it got the meat. Once the dog was able to associate the bell with the meat, it would salivate at the sound of the bell - even if no meat was forthcoming. The bell is the conditioned stimulus, and the meat is the unconditioned stimulus. Eventually, the effect would wear off - the dog would stop salivating at the sound of the bell unless meat was sometimes offered.
Classical conditioning is linked to the "subject-expectancy effect". For example, I might visit a professional healer - a doctor or a psychoanalyst or a counsellor - with a particular issue. The healer might provide some treatment or advice and explain, in an authoritative manner, how my issue will be alleviated. If the healer is convincing in his or her attempt in instilling hope in my heart, my expectations of being cured become high and the good-old placebo effect will kick in and aide me in my recovery. If, on the other hand, the healer is not very positive about my prospects of recovery, there will be a negative expectation on my part and I may become a victim of the nocebo effect.
Another possible explanation might be the power of positive thinking. Positive emotions have been linked to better health. Being in a happy state of mind is associated with decreases in cortisol (the stress hormone implicated in heart disease and cancer) and increased immune function. Being in a positive state of mind also seems to improve treatment outcomes in a lot of chronic ailments.

The placebo effect is best known in relation to pain. People have been known to report a reduction in pain when they think that they are taking a medicine they believe is effective - even though it may just be a sugar-coated tic tac. In such cases, it has been shown by using PET brain scans that this effect is caused by our own brain's production of opioids called endorphins, which reduce pain by plugging into mu-opioid receptors - in much the same way that morphine does. In this scenario, our brain produces pain-dulling chemicals in much the same way that Pavlov's dog salivates at the sound of the bell.

Classical conditioning might explain how the placebo effect is triggered, but it doesn't tell us about the mechanisms that give us the therapeutic benefits.
These days, placebos are commonly used when testing new drugs. Trialling of a new drug usually involves testing on 2 groups of human guinea pigs where one group takes the drug and the other group takes a placebo. Neither group knows what they are taking and, in the case of double-blind trials, neither do the testers. For example, in a trial of a blood-pressure drug in 2000, one third of those who took the placebo reported a reduction in blood pressure. Those who took the drug had a higher success rate, but maybe that was an enhanced placebo effect: they felt a little different after taking the drug, so they truly believed that it wasn't a sugar pill and expected to have an improvement.

Placebo effects have been seen in "cures" for high-blood pressure, cancer, depression, ulcers, and heart disease; how does the placebo effect work in these cases? I don't know, and neither do you. There is a lot of research going on into the mystery of consciousness, but much of what goes on in the brain is unconscious - it happens without our being conscious of it. Knowing about the unconscious - or private life of the brain - could tell us more about ourselves than unlocking the mystery of consciousness. And there is so much we don't know.
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