Where are persons with intellectual disabilities in medical research? A survey of published clinical trials

J Intellect Disabil Res. 2014 Sep;58(9):800-9. doi: 10.1111/jir.12091. Epub 2013 Sep 3.


Background: Persons with intellectual disabilities (ID) are exposed to the same medical interventions as everyone else. Given the unique health profiles of many persons with ID, it cannot be assumed that they will react to medical treatments the same as persons without ID. It is not clear if medical clinical trials routinely include persons with ID. The purpose of this research survey was to examine the inclusion of persons with ID in medical research trials, and to determine whether accommodations and/or study modifications could have been made to promote greater inclusion in medical research.

Method: Three hundred randomised control and clinical trials published between 2007 and 2011 in the six highest impact medical journals were randomly selected. Each study was reviewed for inclusion of persons with ID, and possible accommodations that could have been put in place without compromising research integrity. Corresponding authors received a follow-up survey to determine whether persons with ID were included, but were not mentioned in the article.

Results: Only 6 (2%) of 300 randomly chosen studies clearly included persons with ID. Over 90% of studies were designed in ways that would automatically exclude persons with ID from participating. The author survey revealed three additional studies including persons with ID. Most persons with ID could have participated in at least 70% of the studies with simple accommodations and/or minor procedural modifications.

Discussion: The findings highlight the exclusion of persons with ID in medical research. Efforts are needed to increase inclusion through research policy initiatives and education.

Keywords: ethics; inclusion; intellectual disabilities; medical research.

Publication types

  • Meta-Analysis

MeSH terms

  • Biomedical Research / standards*
  • Clinical Trials as Topic / standards*
  • Humans
  • Intellectual Disability*
  • Patient Selection*