Mentally ill and non-mentally ill defendants’ abilities to understand information relevant to adjudication: A preliminary study. Bulletin of the American Academy of Psychiatry and

The legal construct of competence to stand trial, or "adjudicative competence, " is based on the premise that some mentally disordered defendants have impaired abilities when compared with most defendants and that adjudication should be barred if these competence-related abilities are significantly impaired. Where the line is drawn between sufficient and insufficient abilities has important conse-quences: as a result of being adjudicated incompetent, defendants may be de-tained and treated involuntarily and their trials will be delayed. However, no studies have systematically compared the capacities of relevant groups of defen-dants. In this studv. 84 criminal defendants-42 of whom were hospitalized as incompetent and 4 i b f whom were regarded as unquestionably competent-were administered three instruments measuring capacity to understand legally relevant information. Incompetent defendants performed more poorly on all measures of understanding. Twenty-eight incompetent defendants were administered the mea-sures a second time, after restoration to competence. Restored defendants im-proved their performance on all measures of understanding and their performance was similar to that of normal, competent defendants. Differential legal treatment of defendants with and without mental disorders is based on assumptions about the respec