Competence to stand trial: a neuropsychological inquiry

How might the deconstruction of the legal theory of competence be related to modern neuropsychological models of cognition? To address this question, we examined retrospectively the relationship between clinical judgments of competence of defendants committed to a maximum security psychiatric facility and their neuropsychological test scores on measures of intelligence, memory, attention, academics, and executive function. In addition, based on both neuropsychological and legal theory, we examined whether subtypes of memory, namely episodic and semantic, and intelligence, specifically social intelligence, would have special relevance to these clinical judgements of competence. Results indicated that in relation to the defendants recommended as incompetent to stand trial (IST), defendants recommended as competent to stand trial (CST) scored significantly higher on summary indexes of psychometric intelligence, attention, and memory, especially verbal memory, but not significantly higher on tests of academics or executive function. Moreover, CST defendants scored significantly higher than did IST defendants on selective tests of episodic memory and social intelligence, but not on measures of semantic memory. Partial correlation also revealed a significant relationship between the likelihood of an IST recommendation and lower scores on tests of episodic memory and social intelligence, but not on measures of semantic memory. These findings illustrate the theoretical import of neuropsychological methods and concepts to the burgeoning nomological net known as competence.