Assessing mental capacity – getting it in the right order

Mental health professionals are regularly called upon to assess a patient’s mental capacity to make treatment decisions. Increasingly, psychiatrists are also asked to assess a person’s mental capacity to make decisions about their welfare and their capacity to make financial decisions, particularly where the issue of whether a person has capacity has come before the Court of Protection.

The provisions of the Mental Capacity Act 2005 (the Act) will be familiar to many practitioners working in mental health; specifically, section 2 which provides that mental capacity is matter and time specific and defines the inability of the person to make a decision as being attributable to “an impairment of, or a disturbance in the functioning of, the mind or brain”. The following section of the Act sets out the functional test, which requires those assessing a person’s capacity to consider whether the person is unable to undertake the tasks that underlie the decision-making process. These two sections are at the heart of a mental capacity assessment.

The Supreme Court considered the applicability of the Act in considerable detail in the case of A Local Authority v JB, setting out certain principles as to how sections 2 and 3 of the Act should be construed. It held that the functional test in section 3 must be considered first, so that whether the person is able to undertake the cognitive processes involved in decision-making set out in that section is initially scrutinised, before moving on to the question of whether that inability is due to an impairment of, or a disturbance in the functioning of, their mind or brain. This order of approaching the questions posed in sections 2 and 3 is intended to avoid making the assumption about a person who has a serious mental disorder that the person must obviously be of insufficient understanding to be able to make the relevant decision.

The Supreme Court stated “If the court concludes that P is unable to make a decision for himself in relation to the matter, then the second question that the court is required to address under section 2(1) is whether that inability is “because of” an impairment of, or a disturbance in the functioning of, the mind or brain.  The second question looks to whether there is a clear causal nexus between P’s inability to make a decision for himself in relation to the matter and an impairment of, or a disturbance in the functioning of, P’s mind or brain”[1].

This approach reflects the statutory principles that a person must be assumed to have capacity unless it is established that they lack capacity and is not to be treated as unable to make a decision merely because they make an unwise decision[2].

The Mental Capacity Act Code of Practice, which has not been materially updated since its publication in 2007, still refers[3] to the question of whether the person has an impairment of, or a disturbance in the functioning of, their mind or brain as the first stage of the two stage test.   Practitioners involved in assessing capacity should note that this approach should not be followed given the judgment of the Supreme Court and that local paperwork, policies and training relating to capacity assessments will need to be updated accordingly.

[1] Ibid paragraph 78

[2] Section 1, Mental Capacity Act 2005

[3] Chapters 4.11 to 4.13