Updated: Patients' reactions to finding out they were in the placebo group (created 2005-05-11)

This article was originally published on my old website, but it seems to have disappeared. I'm reproducing it here with a few revisions.

A lot of people have written a lot of things about the use of placebos in research, but one group that hasn't been heard from nearly enough is the patients themselves. A recently published article has changed that trend.

This study was a semi-structured questionnaire given to 42 patients who received placebo in a study of corticosteroid for heel pain. The authors cite a publication that found that more than half of the research studies did not tell anything to their placebo patients after the study ended and that the most common reason given is that such a thought had never even occurred to the researchers.

This is rather sad when you think about it. Patients who participate in research give us a wonderful gift. They cede authority over what treatment they will get. And they give this authority, not to their doctor, but to a random device like a coin flip. These volunteers are willing to endure a fair amount of inconvenience, possibly endure additional pain (for getting extra blood samples, for example), and maybe even suffer an increased level of risk in the study. One way you can show your gratitude to them is by letting know at the earliest possible moment what treatment they did receive. Don't do this during the study, of course, because that destroys all the benefits of blinding and ruins the rationale for using a placebo group in the study. But after the study is over, you should offer this information.

The authors do cite one example, though, where some patients were on a placebo for treatment for depression. They responded well, as you might expect from the placebo effect, but when they were told afterwards that they were on a placebo, most of them relapsed. In another trial, patients who received a placebo surgery were angry when they found out afterwards and demanded the active surgery, even though the research showed that the active surgery was no better than placebo.

This study was a semi-structured questionnaire given to 42 patients who received placebo in a study of corticosteroid for heel pain. The authors cite a publication that found that more than half of the research studies did not tell anything to their placebo patients after the study ended and that the most common reason given is that such a thought had never even occurred to the researchers.

This is rather sad when you think about it. Patients who participate in research give us a wonderful gift. They cede authority over what treatment they will get. And they give this authority, not to their doctor, but to a random device like a coin flip. These volunteers are willing to endure a fair amount of inconvenience, possibly endure additional pain (for getting extra blood samples, for example), and maybe even suffer an increased level of risk in the study. One way you can show your gratitude to them is by letting know at the earliest possible moment what treatment they did receive. Don't do this during the study, of course, because that destroys all the benefits of blinding and ruins the rationale for using a placebo group in the study. But after the study is over, you should offer this information.

The authors do cite one example, though, where some patients were on a placebo for treatment for depression. They responded well, as you might expect from the placebo effect, but when they were told afterwards that they were on a placebo, most of them relapsed. In another trial, patients who received a placebo surgery were angry when they found out afterwards and demanded the active surgery, even though the research showed that the active surgery was no better than placebo.

In the interviews, the researchers found that patients expectations about the trial varied but that some were hopeful to achieve pain relief. Is this an example of therapeutic misconception? The researchers did not discuss therapeutic misconception, which is the tendency for people participating in research to believe that participation in a research trial has to be beneficial to them, even when they are told otherwise. In an article about the special problems of research in rehabilitation medicine, the author notes that

These patients, as well, are likely to agree to participate in just about any type of research in the hope that it will provide some degree of benefit for them, even if they are told this is not likely to be the case. As with spinal cord injured patients, they often ask every time they come to the outpatient clinic whether or not there are any research projects under way that they can volunteer for, without any prompting by the physician. Obviously, the potential for therapeutic misconception is also quite high with this group, and this needs to be considered and addressed by the researcher. www.biomedcentral.com/1472-6939/4/2

The patients were asked to guess which treatment group they were in, and only 55% got it right. This is a question that you should ask at the end of any blinded trial to assure that something (such as a well known side effect of the active drug) did not tip off the patients prematurely.

Most of the participants (83%) welcomed the opportunity to be debriefed about the experiment. These patients also wanted to know about the study results. Again, this should be done in all research. If a subject is participating in research because they want to add to the body of knowledge, one way you can reward them is by telling them what exactly did the research showed.

Some patients were a bit embarrassed when they found out that the beneficial effects they saw were the result of a placebo, but others were amazed and fascinated at experiencing the placebo effect.

There is room for a lot more research like this. We speculate all the time about what practices are ethical and what practices are not. I'm as guilty of this as anyone. But the real test of what is ethical has to incorporate the values, expectations, and beliefs of the research subjects themselves.

This page was written by Steve Simon while working at Children's Mercy Hospital. Although I do not hold the copyright for this material, I am reproducing it here as a service, as it is no longer available on the Children's Mercy Hospital website. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Placebos in research.