Therapeutic misconception not well understood

Put subjects’ comments into context

What IRBs and the research ethics community commonly believe is evidence of therapeutic misconception among research participants often is the result of misinterpretation by the experts, a researcher says.

A new study that looks at therapeutic misconception found that most individuals who enroll in a clinical trial have a desire for a therapeutic benefit, especially when there are no other treatment alternatives, but this motivation does not prevent them from fully understanding randomization.1

“What we found was that pretty much people understood and appreciate the randomization probabilities,” says Scott Y. Kim, MD, PhD, an associate professor in the department of psychiatry and co-director of the Center for Bioethics and Social Sciences in Medicine at the University of Michigan in Ann Arbor.

Kim was the principal author of a study that looked at how individuals made decisions about whether to enroll in a Parkinson’s disease clinical trial that involved randomization to a gene-transfer arm or a sham surgery arm.1

Participants of the trial received surgery to their heads for a gene transfer if they were in the intervention arm. The sham arm participants had a hole drilled in their heads, but nothing was implanted in their brains, Kim explains.

Investigators asked participants: “What are the chances of a participant being assigned to the sham surgery group [or gene transfer group]?” They designed this question be in the third person to ascertain their intellectual comprehension of randomization ratios. The randomization ratio for this trial was one to one, so a correct answer would be 50%.1

A second question they asked participants was similar but more personal, to see if they could apply the information to themselves: “What do you think your chances are of being assigned to sham surgery [or gene transfer group]?”1

For the first question, 83% of respondents said there was a 50% chance of assignment to either arm. For the second question, 55% gave the correct quantitative answer as well as making a variety of comments, while the remainder only made various qualitative comments. The comments were similar in two groups, and at first appeared to show a misconception, such as “I’d be disappointed if I don’t get the real thing.” But Kim and co-researchers noticed that people who clearly both understood and applied the randomization probabilities to themselves also made the same types of concerning comments.1

As they analyzed these comments, it became apparent that participants were communicating something other than their knowledge of randomization probabilities, Kim says.

“They made a lot of comments that if taken in isolation would have suggested they didn’t know what was going on,” he explains. “They seemed to be saying, ‘I’ll be surprised if I don’t get the real thing — meaning the gene transfer intervention.’ The person may say that but have correctly answered everything to that point. How do you interpret that?”

But then, they would talk about how many people are praying for them, or their hope that positive thinking will make a difference, or even express their belief in “luck,” Kim notes.

Taking the context into consideration, IRBs and bioethicists might look at this apparent incongruity as being similar to what happens when people identify with a particular sports team, Kim suggests.

One’s team might have a losing record this season and be slated to play on Saturday against a team with a no-loss record. Objectively, most people would predict the opposing team to come out victorious, but the person who favors the hometown team might reframe the match-up, saying there was a good chance their team might pull an upset, he explains.

“In terms of probability, this makes no sense, but the person is obeying the rules of a sports conversation,” Kim adds. “If we understand the context in which they’re making these statements it might be quite rational.”

The concept Kim and co-researchers believe IRBs and bioethicists need to pay more attention to is the notion of pragmatics in linguistics: “How people communicate and convey meaning by the context — not just by the semantic meaning of words,” Kim says. “It’s like when someone asks, ‘Can you pass the salt?’ We all understand what they mean by the context.”

When evaluating the quality of informed consent in a study, IRBs and researchers might consider the context.

“If you violate the norms of conversation, you will create confusion — for example, providing excessive reassurances in a study with minimal risk,” Kim says. “It is a problem because IRBs are so used to requiring it they accept it as a conventional way of doing things. But it’s not conventional for the subjects.”

The study’s conclusion is that most people who have serious illnesses and enter a clinical research trial do have a therapeutic motivation, meaning they hope to benefit from being in research and will focus on that motivation because for them, that is what is on their minds, he adds.

“But this doesn’t mean they do not know what they’re getting into,” Kim says.


  1. Kim SYH, de Vries R, Wilson R, et al. Research participants’ “irrational” expectations: common or commonly mismeasured? IRB: Ethics & Hum Res. 2013;Jan-Feb:1-9 [e-pub:]