Can clinicians and carers make valid decisions about others' decision-making capacities unless tests of decision-making competence and capacity include emotionality and neurodiversity?

Design/methodology/approach – The approach is to discuss current guidance and practice, and to offer academic criticism and explanation.

Findings – The findings include the discovery that the Mental Capacity Act 2005 Code of Practice suggests that healthcare professionals and family/carers may undertake assessments of decision‐making capacity, yet the guidance it provides for their doing so overlooks salient issues. Many of those involved in the daily lives of those, who may lack decision‐making capacity (and thus be seen as legally incompetent) such as the learning disabled, demented, mentally ill and neurodiverse, must decide whether to respect their decisions as competent, or to disregard the decisions on the grounds of incompetence and to act in the person's best interests. As many will lack training in their clinical and legal responsibilities and liabilities, it is crucial that they, and those they care for, are protected by not only an increased knowledge of mental capacity legislation and practice, but also how it may apply to questions of emotionality and neurodiversity.

Originality/value – This paper expands and builds on the authors' previous research into including emotionality in assessments of capacity, and will be of use to practitioners in the field of learning disability, and other psychiatric specialities.