For eons, doctors have advised patients to take two aspirin and call back in the morning. Now researchers are trying to find out whether the patient would do as well to skip the aspirin but, yes, call back.
The placebo effect, the nonspecific reason people respond to treatments that are not proven to work on their disease--treatments as simple as talking to a doctor--has suffered from a bad reputation. But a small but stalwart group of researchers is looking for ways to convince the medical world to pay it homage.
"There's good science," says Daniel Moerman, a medical anthropologist at the University of Michigan-Dearborn and leading authority on the subject. "But most of the time people don't pay attention to what is happening" in the group that gets the placebo.
Moerman's 1975 article showing how people in different cultures responded to disease set the stage for an increasing interest worldwide in the placebo phenomenon. At the time he began his research into the placebo effect, most researchers were trying to find ways to eradicate it.
Anybody who got better on a placebo must be psychologically suggestible, the thinking went. So clinicians in the 1970s tried to eliminate participants they thought would buckle in clinical trials. They tested participants for assertiveness and independence, and in the push to eliminate "defective people," Moerman says, they sometimes struck out all the women.
But support for the placebo effect has grown with each new sign that it may be extraordinarily powerful.
* It explains why patients who were taken off blood-pressure medicine for three weeks so they could try a new drug saw their blood pressure drop to normal in the period when they were taking no drug at all.
* It explains a 1993 discovery that thousands of elderly Chinese Americans in California born in years with bad astrological qualities died sooner from cancer than Chinese Americans with the same disease who were born in good astrological years. This difference, gleaned from an examination of 30,000 death certificates, appears linked to cultural beliefs about fate. A study of whites with the disease revealed no similar correlation of cancer deaths and astrological signs in birth years.
* A pilot study of placebo, or pretend, knee surgery on 10 Houston veterans hospital patients produced such startling results that doctors are now testing it on 180 patients.
The original test involved three groups of patients with osteoarthritis. Everybody--the patients who were operated on, the ones who thought they were and those who got no surgery at all--reported pain relief six months later. Four of the five placebo patients believed the surgery was worthwhile and said they would recommend it to a friend.
People's expectations that they will improve, cultural beliefs and the enthusiasm of the treating doctor all may be at work in the placebo effect, these examples show.
Other nonmedical events also can trigger a biological response as a placebo apparently does. The example Moerman gives is blushing. An embarrassing remark brings blood to the cheeks. A red face is a biological response to something--verbal or visual--outside the body.
The mechanism that sets it off is what researchers are after. How can a placebo and morphine both trigger brain reactions that ease pain?
A study reported in May appears to show that the change in brain activity that accounted for improvement in patients on Prozac is precisely opposite to the change in brain activity experienced by patients who took a placebo--and yet they too got better.
Placebo is a pretty good painkiller. A saline injection was enough to kill the pain in 30% to 40% of people who got their wisdom teeth out, according to one study a few years ago at the University of Maryland. A symbolic injection stimulated patients' production of morphine endorphins in a 20-year-old California study.
Research now shows that placebo might be as good as antidepressants for some patients.
Irving Kirsch, professor of psychology at the University of Connecticut, co-wrote a controversial journal article reporting that placebos do as well as whole classes of antidepressants, including Prozac, 75% of the time.
He and others say the reason is expectation--people get better if they expect to.
This is thought to account for the findings in perhaps the most famous study of the placebo effect in surgery. In the 1958 study, patients underwent sham surgery for angina (pain due to a constricted blood supply). They got local anesthesia and were cut slightly, but they did better than patients who actually had the surgical procedure.
The procedure, ligation of the arteries, is no longer done.
The manner of a doctor also may affect how fast treatment takes hold, many researchers now believe. That explains why impostor "doctors" who have never gone to medical school can successfully treat patients.
It also explains why, for more than 2,000 years, patients have reported improvement from such unscientific medical treatments as blood-letting. A 1955 study by Harvard University researcher H.K. Beecher estimated that the placebo effect explains a good outcome 30% of the time. Researchers such as Moerman think it could be as high as 50%.