Interpersonal influences on decision-making capacity: a content analysis of court judgments.

For many purposes in England and Wales, the Court of Protection determines whether a person has or lacks capacity to make a decision, by applying the test within the Mental Capacity Act 2005. This test is regularly described as a cognitive test with cognitive processes discussed as internal characteristics. However, it is unclear how the courts have framed interpersonal influence as negatively impacting upon a person's decision-making processes in a capacity assessment context. We reviewed published court judgments in England and Wales in which interpersonal problems were discussed as relevant to capacity. Through content analysis, we developed a typology that highlights five ways the courts considered influence to be problematic to capacity across these cases. Interpersonal influence problems were constructed as (i) P's inability to preserve their free will or independence, (ii) restricting P's perspective, (iii) valuing or dependence on a relationship, (iv) acting on a general suggestibility to influence, or (v) P denying facts about the relationship. These supposed mechanisms of interpersonal influence problems are poorly understood and clearly merit further consideration. Our typology and case discussion are a start towards more detailed practice guidelines, and raise questions as to whether mental capacity and influence should remain legally distinct.