Assessment of consent capability in psychiatric and medical studies.

In order to evaluate psychiatric factors that potentially influence assessment of consent capacity, 195 IRB members read summaries of hypothetical medical (cancer vs. neuropathic pain) and psychiatric trials. They then rated research participants' capacity for consent (capable or not capable), autonomy, and decisional abilities, as well as the legal risk to the institution of the study. Levels of depression information varied across the medical disorders. Significantly fewer IRB members judged participants in the depression trial to possess adequate capacity for consent relative to 4 of 6 medical conditions; legal risk to the institution also was rated higher in the psychiatric study. While IRB members judged participants in depression trials to have less capacity for consent and to pose higher levels of institutional risk than medical trial participants, the addition of increasing information regarding depressive co-morbidities had little or no effect on judgments of medical studies. Implications are discussed relative to the apparent overprotection of participants in psychiatric trials and underprotection of those in medical trials.