The UK Mental Capacity Act and consent to research participation: asking the right question.

This paper considers the meaning of the term 'intrusive research', as used in the UK Mental Capacity Act 2005 (MCA), in relation to studies in which an informant is asked to provide information about or on behalf of a person who lacks capacity to consent, and who is not otherwise involved in the study. The MCA defines 'intrusive research' as research that would legally require consent if it involved people with capacity. The relevant ethical principles are that consent should be sought from people who would be affected by a piece of research and that this requirement should be implemented proportionately. The critical question, for investigators and research ethics committees, is: would provision of the personal information specified in the research protocol significantly affect a person whose capacity is not impaired? If the answer to this question is 'no', then the study falls outside the definition of 'intrusive research', and the MCA does not apply.