The causative nexus is an essential part of any mental capacity assessment as it provides a clear rationale for whether the person being assessed has capacity to make a specific decision.
Making a professional case
When completing a mental capacity assessment, it is important that the assessor give a clear justification for the outcome. The bigger the decision and possible implications, the more details should be included, as assessments may well be reviewed by the Court of Protection (COP), Care Quality Commission (CQC) or other professional monitoring bodies.
In order to make this process simpler, we can consider the assessment through the lens of the two-stage test, separating arguments based on diagnostic and functional steps.
Worked example – part 1
Decision being assessed:
Whether Mx D can continue to use her gas stove and cooker independently, or if the gas to these kitchen items should be turned off when no supervised support is present.
- Mx D was unable to demonstrate understanding of the relevant matters surrounding the use of the gas cooker, including safety.
- Mx D was further unable to show the ability to retain the relevant information around using her gas cooker to make a decision around it use.
- Based upon which, Mx D could not use the information provided, even with graded support to weigh up the decision to continue to use the gas cooker in her everyday meals at home.
- While Mx D can communicate articulately around this matter during the assessment, Mx D could not maintain focus upon the relevant topic.
- It is therefore my professional opinion that Mx D could not demonstrate the functional ability to make her own decision to continue using the gas cooker independently within her home.
- Diagnostic step:
- Mx D has a no formal diagnosis at this time, being only recently in receipt of care services. Service input started after several concerns raised by neighbours after fire alarms going off, alongside police reports of being found walking in her night dress in town appearing disorientated and confused.
- Mx D was unable to engage with a full ACE III, however, took part in a MMSE, scoring 14/30, suggesting a cognitive impairment is present.
It is at this stage that we apply the causative nexus. Put simply, the causative nexus is the glue or link that draws the argument together, providing the rationale for a conclusion of capacity or incapacity to make a specific decision. It is directed by the question: ‘Is the person’s inability to make the decision caused by the identified impairment or disturbance of the brain?’
Worked example – part 2
- Therefore, based upon the diagnostic and functional steps, it is my professional opinion that the cognitive impairment is directly affecting Mx D’s ability to make the decision to continue to use her gas cooker independently at home. This is witnessed through reduced attention, decreased short-term memory and impaired processing skills that directly impact Mx D’s cognitive functioning and decision making.
- I have drawn this conclusion because Mx D was unable to remain focused on the topic being discussed, quickly diverting onto topics of her photos on, the window ledge, organising stacks of items that were positioned around her or getting up to look out the window, voicing her friend was due to visit soon. Through reports provided, this short-term attention has caused increasing risks of fires or gas leaks as Mx D has forgotten they had started a meal. On discussion, Mx D could not recall items being cooked on the gas stove, moving swiftly onto topics influenced by their environment.
Reflecting on the assessment
In this example, we have simplified the report in order to highlight the key details and draw attention to the links between the functional and diagnostic steps, followed by the causative nexus.
In a full assessment report, the assessor should include detail of the interview itself, plus expanded rationale for each step. If there is ever any doubt, we suggest this simple rule of thumb: if something is not recorded, then (for the purpose of the assessment) it did not happen. Good, detailed record keeping is therefore absolutely essential.