This chapter considers how the law might be reformed so as to better capture circumstances in which an agent’s capacity for autonomous decision-making is being undermined by a disorder or impairment which affects the values or beliefs that the agent applies to the information. It will begin by exploring the merits of including an ‘appreciation’ criterion in the test for capacity, before going on to consider whether more other, more explicit, criteria would be preferable. It will conclude that the challenges inherent in devising a workable legal test lean in favour of the law adopting a more blunt approach which focuses on the origins of the values or beliefs that the agent applies to the information in their decision-making. A new limb of the MCA is therefore proposed, which asks whether the person is unable to make a decision because the values or beliefs by which they evaluate the relevant information have been caused by or altered as a consequence of the person suffering from a disorder, illness, or impairment. Various potential challenges to such a provision will be explored and responded too.