Reconsidering research exclusion for serious mental illness: Ethical principles, current status, and recommendations

Background: Historically, individuals managing serious mental illness (SMI) have often been excluded from research, typically because of concern that these individuals may not be able to understand and provide truly informed consent. As treatment has improved, the assumption that individuals managing SMI may not be capable of consent needs to be re-examined. Systematic exclusion from research may limit empirically tested treatments available for people managing SMI, and may contribute to the health care disparities seen in this population. Objectives: This article examines this issue by documenting current rates of research exclusion for high disease burden conditions, based on empirical review of studies in ClinicalTrials.gov. Research design: Current rates of exclusion from studies for psychiatric conditions were assessed through systematic review of relevant clinical trials on ClinicalTrials.gov. Subjects: Subjects in this inquiry are either articles accessed in the literature reviews, or descriptions of studies in public data on ClinicalTrials.gov. Measures: The primary measure was a previously published coding system to document the extent and types of research exclusion related to psychiatric status. Results: Among studies of interventions for substance use disorders and chronic pain, individuals managing SMI were more likely to be excluded than those with other psychiatric disorders at statistically significant levels. This was not the case among studies of interventions for ischemic heart disease. In studies of substance use disorders, 9% explicitly excluded SMI and 83% could exclude people with SMI based on broader exclusion criteria. In studies of chronic pain these two categories of exclusion were 16% and 55%, and in studies of ischemic heart disease, these two categories of exclusion were 1% and 20%. Conclusions: Evidence indicates that it is ethically and scientifically more appropriate to exclude based on capacity to consent than membership in the group of individuals managing SMI. The discussion outlines techniques researchers can use for more equitable and generalizable sampling.