In previous blogs, we have explored some of the many different elements required to assess mental capacity for a specific decision. This brings us then to the two stage test, which is composed of the functional and diagnostic steps that are then bound together as part of the causative nexus (the justifiable link).
The diagnostic step
The second part of the two stage test has two elements to it:
- Does the person have an impairment or disturbance of the brain? (Diagnostic)
- And if so, does this impairment or disturbance of the brain directly affect their ability to make the specific decision being addressed in the assessment? (Causative Nexus)
An impairment or disturbance of the brain can be any short- or long-term condition that impacts the individual’s decision-making. This may include drugs and alcohol, an infection, dementia, brain injury etc.
However, it is important to note that the individual does not necessarily need a formal diagnosis. It is the assessor’s role to demonstrate and justify that there is an impairment or disturbance of cognitive functioning present at the time of the assessment that is impacting on decision-making. If no formal diagnosis has been given, then a greater level of evidence would be required.
If the impairment is the result of a short-term condition, it is advised that the decision be delayed (if at all possible) until the person has regained capacity.
Cognitive impairment and mental capacity
In the case of North Bristol NHS Trust v R (2023, EWCOP 5) the question of whether a formal diagnosis is required to meet the diagnostic aspect of the two stage test was raised before the courts. From which, Judge MacDonald directed that the formulation of the matter in which the person is believed to be unable to demonstrate capacity must be well established before reaching the diagnostic element, ensuring a clear decision identified, relevant information established, supported capacity upheld and functional elements clearly documented.
From here, if necessary, the diagnostic and causative nexus can be considered. This is summarised in paragraphs 47 and 48 of the judgement:
‘In this context, the question of whether any inability of R to make a decision in relation to the matter in issue is because of an impairment of, or a disturbance in, the functioning of the mind or brain is a question of fact for the court to answer based on the evidence before it. […] The words “impairment of, or a disturbance in” are not further defined elsewhere in the [Mental Capacity] Act. In these circumstances, there is no basis for interpreting the statutory language as requiring the words “impairment of, or disturbance in” to be tied to a specific diagnosis. Indeed, it would be undesirable to do so. To introduce such a requirement would constrain the application of the Act to an undesirable degree, having regard to the complexity of the mind and brain, to the range of factors that may act to impair their functioning and, most importantly, to the intricacies of the causal nexus between a lack of ability to take a decision and the impairment in question.’North Bristol NHS Trust v R (2023, EWCOP 5), paragraph 47
‘In the foregoing circumstances, a formal diagnosis may constitute powerful evidence informing the answer to the second cardinal element of the single test of capacity, namely whether any inability of R to make a decision in relation to the matter in issue is because of an impairment of, or a disturbance, in the functioning of the mind or brain.’North Bristol NHS Trust v R (2023, EWCOP 5), paragraph 48
Professional advice and support
Clearly, there are many factors that need to be considered when conducting a Mental Capacity Assessment. In cases where there may be an impairment or disturbance of the brain but has not been formerly diagnosed, it is essential that the assessment is conducted thoroughly and documented to a high standard. Equally, as the judgement above states: just because an individual has a diagnosed impairment or disturbance of the brain does not mean that they automatically lack capacity.