Credibility and comprehension of healthy volunteers in lengthy inpatient drug studies.

Early clinical trials rely upon paid healthy volunteers. Concern has been raised regarding the characteristics of these individuals, how well they understand their rights and the risks of clinical research, and how they may be influenced by manipulation or coercion. Therefore, we investigated (1) the motivations of subjects in clinical trials, (2) how well these individuals comprehend a consent form they sign, and (3) the effect of the stipend on the reliability of information reported by volunteers in clinical trials. Thirty healthy subjects (age, 21-45 years) in a long-duration clinical trial were administered a questionnaire gathering demographic information and testing their comprehension of the consent form. In a separate chart review of 10 clinical trials, 374 subjects were studied to determine their reliability in reporting abnormalities in their medical history and in reporting adverse events, and an association was examined between the incidence of unreliable reporting and the stipend paid to them for participating in the clinical trial. A large percentage of subjects who were enrolled in the long-duration clinical trial failed to comprehend a variety of basic concepts related to the consent form and their participation in the drug study. The chart review demonstrated that subjects who are paid larger stipends may not be more likely to report abnormalities on their medical history. Further studies should be undertaken with larger numbers of subjects enrolled in clinical trials, and possible associations between demographic data (eg, income, level of education, number of previous studies) and the reliability of information provided by normal healthy research volunteers should be examined.