Best interests decision-making under the Mental Capacity Act

The Mental Capacity Act (MCA) 2005 states that ‘[a]n act done, or decision made, under this Act for or on behalf of a person who lacks capacity must be done, or made, in his best interests’. Despite the statutory checklist set out in section 4 enumerating elements that are to be taken into account when determining someone’s best interests, the meaning of the notion is not entirely clear. In the context of surrogate decision-making, best interests is often contrasted to the substituted judgment standard; while the former is said to set ‘objective’ criteria for decision-making on behalf of others, the latter is based on the principle of respect for autonomy and instructs the surrogate to make a decision that the person would have made if he or she had the capacity to do so. Although the notion of ‘best interests’ appears quite early in the case law of British courts exercising the Crown’s parens patriae jurisdiction, the application of the standard, as incorporated in the MCA today, raises some fundamental questions:

• How does best interests in the English framework relate to the substituted judgment standard?
• What factors can be taken into account when assessing best interests? Besides physical well-being, is it possible to consider the incapacitated person’s emotions, values, past preferences or present feelings when determining best interests?
• How to balance different factors of best interests against each other? Most notably, how to balance the past and present wishes of the incapacitated person against ‘objective’ welfare elements? Do all factors weigh the same or are there predominant factors that might determine the outcome of the decision? Does the physical well-being of the patient always trump other considerations?
• Whose interests can be taken into account? Should the interests of the family members or carers influence the outcome of a best interests assessment?

The aim of this document is to facilitate a better understanding of the meaning of best interests through the analysis of the relevant case law and the examination of the statutory framework. Emphasis will be placed on the genesis and the historical evolution of concept since it seems essential for the proper understanding of the meaning of the contemporary legal standard.

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