Assessing the ability of people with a learning disability to give informed consent to treatment.

BACKGROUND: People with a learning disability are increasingly being encouraged to take a more active role in decisions about their psychological and medical treatment, raising complex questions concerning their ability to consent. This study investigates the capacity of people with a learning disability to consent in the context of three treatment vignettes, and the influence of verbal and memory ability on this capacity.
METHODS: Measures of verbal ability, memory ability and ability to consent to treatment (ACQ) were administered to 40 people with a learning disability. The ACQ consisted of three vignettes depicting a restraint, psychiatric or surgical intervention. These were followed by questions addressing people's ability to understand the presenting problem; the nature of the proposed intervention; the alternatives, risks and benefits; their involvement in the decision-making process; and their ability to express a clear decision with a rationale for treatment.
RESULTS: Five people (12.5%) could be construed as able to consent to all three vignettes; 26 (65%) could be construed as able to consent to at least one. The questions that were most difficult to answer concerned a participants' rights, options and the impact of their choices. Verbal and memory ability both influenced ability to consent.
CONCLUSIONS: This study introduces a measure that may enable clinicians to make more systematic assessments of people's capacity to consent. A number of issues surrounding the complex area of consent to treatment are also raised.