Assessing the capacity of people with intellectual disabilities to be witnesses in court

Background. People with intellectual disabilities who have been victims or other witnesses of crime have had limited access to the criminal justice sy stem, often on the basis of assumptions about their incapacity to be interv iewed by the police and to give evidence in court. The aim of this study wa s to assess their capacity to be witnesses in court. Methods. Forty-nine men and women with intellectual disabilities, all of wh om were potential witnesses of ii-treatment, were assessed in order to prov ide advice, initially to the police, about their capacity to be interviewed for judicial purposes. The assessments included evaluations of each person 's intellectual ability, memory, acquiescence, suggestibility, and their ab ility to explain concepts relating to the oath. Results. Only 37 (76%) were able to complete the assessments. Most of those with a Full Scale IQ score of greater than or equal to 60 had a basic unde rstanding of the oath, compared with only a third of those with IQ scores b etween 50 and 59, and none of those with IQ scores < 50. Nevertheless, some of the people who were unable to demonstrate an understanding of the oath did understand the words 'truth' and 'lie', especially when asked about the se concepts in relation to concrete examples. Conclusions. While intellectual ability appears to be the best overall pred ictor of the capacity of people with intellectual disabilities to act as wi tnesses, confining witnesses to those who could explain the meaning of the oath would mean that a number of persons who might be interviewed by the po lice and subsequently appear in court could be excluded from the judicial p rocess.