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Decision-making capacity for treatment in psychiatric and medical in-patients: cross-sectional, comparative study
Gareth S Owen1, George Szmukler, Genevra Richardson
1Gareth S. Owen, PhD, MRCPsych, Department of Psychological Medicine, King's College London, Institute of Psychiatry, London, UK; George Szmukler, FRCPsych, Department of Health Service and Population Research, King's College London, Institute of Psychiatry, London, UK; Genevra Richardson, LLM FBA, School of Law, King's College London, UK; Anthony S. David, FRCPsych, Department of Psychological Medicine, King's College London, Institute of Psychiatry, London, UK; Vanessa Raymont, MRCPsych, Centre for Mental Health, Department of Medicine, Imperial College, London, UK, and Department of Radiology, Johns Hopkins University, USA; Fabian Freyenhagen, PhD, Wayne Martin, PhD, School of Philosophy and Art History, University of Essex, Wivenhoe Park, Essex, UK; Matthew Hotopf, PhD, MRCPsych, Department of Psychological Medicine, King's College London, Institute of Psychiatry, London, UK.
Background:
Is the nature of decision-making capacity (DMC) for treatment significantly different in medical and psychiatric patients?
Aims:
To compare the abilities relevant to DMC for treatment in medical and psychiatric patients who are able to communicate a treatment choice.
Method:
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.
Results:
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<0.001). Appreciation was a better 'test' of DMC in the psychiatric hospital (where psychotic and severe affective disorders predominated) (P<0.001), whereas reasoning was a better test of DMC in the medical hospital (where cognitive impairment was common) (P = 0.02).
Conclusions:
Among those with good understanding, the appreciation ability had more salience to DMC for treatment in a psychiatric setting and the reasoning ability had more salience in a medical setting.
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