Mental Capacity and Consent to Treatment in Psychiatric Patients

The State of the Research

Paola C. Candia; Alfredo C. Barba


Curr Opin Psychiatry. 2011;24(5):442-446. 

In This Article

Mental Retardation

Children with mental retardation are presumed incompetent just as all children are, as a matter of legal status. However, for adults with mental retardation, depending on the severity of impairment, their treatment consent capacity varies considerably. In a study that compared mild (IQ 55–80) and moderate mental retardation (IQ 36–54) adults with non-mental retardation controls on treatment consent capacity for low-risk elective treatment procedures, most mild mental retardation adults' understanding and choice abilities were similar to those of controls, but mild mental retardation adults were significantly more impaired than controls on the appreciation and reasoning abilities.[35] In another study, 18–68% of mild mental retardation and 4–34% of moderate mental retardation adults performed in the range of the normal individuals. Appreciation performance was better (74–92%) but the reasoning performance was much worse.[8] One study compared persons with chronic psychosis, dementia, and mental retardation.[36] Using a semistructured measure for capacity, the author determined incapacity rates of 10% among psychotic patients, of 35% among the mental retardation group (mean IQ = 60.2), and 67% among the dementia group.[36]


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