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.
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Reactions to treatment debriefing among the participants of a placebo controlled trial.
Di Blasi Z, Crawford F, Bradley C, Kleijnen J. BMC Health Serv Res 2005: 5(1); 30.
[Medline] [Abstract]
[PDF]
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.
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Informing participants of allocation to placebo at trial closure: postal survey. Di
Blasi Z, Kaptchuk TJ, Weinman J, Kleijnen J. Bmj 2002: 325(7376); 1329.
[Medline] [Abstract]
[Full text]
[PDF]
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.
