Concerns have been raised that persons with serious illnesses participating in high risk research, such as Parkinson disease (PD) patients in sham surgery trials, have unrealistic expectations and are vulnerable to exploitation. A comparison of enrollees and decliners of such research may provide insights about the adequacy of decision-making by potential subjects.

We compared 61 enrollees and 10 decliners of two phase 2 neurosurgical intervention (cellular and gene transfer) trials for PD regarding their: demographic and clinical status; perceptions and attitudes regarding research risks, potential direct benefit, and societal benefit; and perspectives on the various potential reasons for and against participation. In addition to bivariate analyses, a logistic regression model examined variables regarding risks and benefits as predictors of participation status.

Enrollees perceived lower risk of harm while tolerating higher risk of harm, were more action oriented, but did not have more advanced disease. Both groups rated hope for benefit as a strong reason to participate, while the fact that the study’s purpose was not solely to benefit them was rated as ‘not a reason’ against participation. Hope for benefit and altruism were rated higher than expectation of benefit as reasons in favor of participation for both groups.

Enrollees and decliners are different in their views and attitudes toward risk. Although both are attracted to research due to hopes of personal benefit, this hope is clearly distinguishable from an expectation of benefit and it does not imply a failure to understand the main purpose of research.