After 50 years of acceptance serious doubts have appeared

Jan 26, 2006 15:36 GMT  ·  By

Suppose you have an illness and the doctor tells you "I'll give you this medication", but instead, in reality he only gives you a sugar pill. And then, suppose you get better. What happened? Was it that your mental powers and your good state of mind helped your body cure itself? Or suppose you are in great pain and the doctor instead of giving you morphine, he gives you a saline solution while just pretending to give you morphine. Nonetheless, your pain vanishes. How does this happen?

The pain release might be biochemical after all?

Fabrizio Benedetti of the University of Turin in Italy conducted the classical experiment with a twist. For several days he gave morphine to a patient. Then, at some point he gave the patient a saline solution instead of morphine. The saline solution worked exactly like morphine. This is the classic Placebo effect. However, in another case he gave the patient a slightly modified Placebo: the saline substance was mixed with a substance called naloxone. In this case the Placebo effect didn't appear. The patient didn't feel any pain release. What happened?

The explanation isn't very complicated: The classical Placebo works because it simply reduces the patient's anxiety and stress. This triggers (or is another name for) the release of endorphins, our bodies' natural painkillers. However, naloxone is a drug that blocks endorphins. This is why in the second case the Placebo solution didn't work, although the patient was still having the same expectations. Nonetheless, his brain was prevented from generating the endorphins, thus pain continued.

The Placebo cure is no better than the cure without any Placebo

There's one thing to say that Placebo works as a painkiller and yet another thing to say that it can actually cure you. Dr. Asbjorn Hrobjartsson and Dr. Peter C. Gotzsche of the University of Copenhagen and Nordic Cochran Center reviewed journal articles looking for the original research stating that as high as 35% of patients improve if given a placebo. All the papers cited some reference. The paper being referenced cited another reference. It turned out that the original source of the statement was a 1955 article - "The Powerful Placebo" by Henry Beecher, who had been chief of anesthesiology at Massachusetts General Hospital in Boston. Dr. Beecher had analyzed about a dozen studies and came up with the 35-percent figure. Apparently everybody took this for granted.

The Danish doctors observed that the original study by Dr. Beecher had one serious problem: it lacked a control group. Dr. Beecher compared how many patients on Placebo get better compared to the patients on the real drug, but he didn't check how many patients get better when no drug or Placebo whatsoever is administered to them.

Then, to get the issue straight, the Danish doctors analyzed 114 studies published between 1946 and 1998 that had all the three groups of patients. To the doctors' surprise, patients in the third group (who received nothing) improved as often as those in the placebo group. In addition, they could find no objective measure of improvement in the placebo group, such as lowered blood pressure. The studies involved about 7,500 patients with 40 different medical conditions, including medical disorders such as high blood pressure, high cholesterol levels and asthma; behavioral disorders and addictions, like alcohol abuse and smoking; neurological diseases like Alzheimer's disease, Parkinson's disease, epilepsy, and infections, like bacterial infections and the common cold.

Thus, although Placebo may work as a painkiller, because patients simply expect the drug to work and get more relaxed, Placebo cannot be expected to work as an actual cure for any illness.

Photo credits: small stones, labelled bottle (Germaine Koh)