Decision-making capacity for treatment in psychiatric and medical in-patients: Cross-sectional, comparative study

Is the nature of decision-making capacity (DMC) for treatment significantly different in medical and psychiatric patients? To compare the abilities relevant to DMC for treatment in medical and psychiatric patients who are able to communicate a treatment choice. A secondary analysis of two cross-sectional studies of consecutive admissions: 125 to a psychiatric hospital and 164 to a medical hospital. The MacArthur Competence Assessment Tool - Treatment and a clinical interview were used to assess decision-making abilities (understanding, appreciating and reasoning) and judgements of DMC. We limited analysis to patients able to express a choice about treatment and stratified the analysis by low and high understanding ability. Most people scoring low on understanding were judged to lack DMC and there was no difference by hospital (P = 0.14). In both hospitals there were patients who were able to understand yet lacked DMC (39% psychiatric v. 13% medical in-patients, P