Intellectual deficits and restoration to competency to stand trial: An examination of IQ cut off scores

Abstract

Intellectual functioning impacts defendants’ competence to stand trial, though research on this population remains limited. This study replicated and advanced prior work, focusing on defendants’ demographic, clinical, cognitive, and criminal justice variables and their association with length of hospitalization and restoration determinations. Participants were 74 male and female criminal defendants in a midwestern state who were adjudicated incompetent to stand trial, had a diagnosis related to intellectual deficits, and completed competency restoration. Most defendants (83.7%) were restored to competency. Demographic factors were unrelated to restoration outcomes; violence of alleged offense predicted shorter hospitalization. Receiver Operating Characteristic Curve analyses determined an IQ score cut-off of 63.5 for which participants were of greater likelihood to be determined restored, providing guidance on the likelihood of restoration for defendants with intellectual disability related diagnoses. Specifically, this score can be used with clinical data to inform competency determinations for defendants with cognitive deficits.