The Mental Capacity Act 2005 sets out a framework for assessing decision-making capacity and this is supported by the Mental Capacity Act Code of Practice (Department for Constitutional Affairs, 2007). The Court of Appeal in Re T (Adult: Refusal of Treatment) [1992] held that the right to make decisions presupposes an ability or capacity to do so. The presumption in law is that adults and young people have the capacity to consent to an examination and treatment and it is for the nurse to show otherwise through an assessment of decision-making capacity (Mental Capacity Act 2005, section 1).
Capacity is the key to autonomy and the test of capacity under the Mental Capacity Act 2005 is based on a test of understanding that requires the person to understand information relevant to the decision, to retain that information and to use the information when making a decision that they communicate to the nurse (Mental Capacity Act 2005, section 3). It is not a professional or status test and a nurse cannot assume a patient lacks capacity because of that person's age, physical appearance, condition or other aspect of their behaviour (Mental Capacity Act 2005, section 2).
Assessing decision-making capacity
The assessment of a person's decision-making capacity requires the methodical application of the provisions of the Mental Capacity Act 2005 and its code of practice.
The test for decision-making capacity is a two-stage functional test that relates to a specific decision to be made at that time. That is:
Time and issue specific
The wording of the Mental Capacity Act 2005, section 2 confirms that:
‘A person lacks capacity in relation to a matter if at the material time he is unable to make a decision for himself in relation to the matter because of an impairment of, or a disturbance in the functioning of, the mind or brain.’
The code of practice to the Mental Capacity Act 2005 (Department for Constitutional Affairs, 2007) explains that:
‘An assessment of a person's capacity must be based on their ability to make decisions at the time it needs to be made, and not on their ability to make decisions in general.’
Decision-making capacity is therefore considered both issue specific and time specific. A person may have capacity in respect of certain matters but not in relation to other matters. Equally, a person may have capacity at one time and not at another.
Fluctuating capacity
Fluctuating capacity can occur when a person's condition is cyclical in nature, moving from an acute phase to a period of recovery as is seen with many enduring physical and mental health problems (TX v Local Authority [2014]). During the acute phase, a person may lose the ability to make decisions, an ability which might then return during the recovery phase.
The time- and decision-specific approach to assessing decision-making capacity can be challenging when a person has fluctuating capacity (PC v York City Council [2013]). A person may have decision-making capacity when assessed, but appear to lack capacity shortly after the assessment and are unable to put their decision into effect as a result. The view outlined in the code of practice to the Mental Capacity Act 2005 (Department for Constitutional Affairs, 2007) is that the same time- and decision-specific approach should apply in cases of fluctuating capacity and that assessors should consider waiting until capacity is restored before asking the person to make the decision.
The Court of Protection, however, argues that, while this approach is likely to be of use in situations where one-off decisions need to be made, such as consent to a surgical procedure or making a will, it is less useful when the decision is one that needs to be repeated, sometimes on a daily basis.
Micro- and macro-decisions
In Greenwich RLBC v CDM [2019] the court was asked to consider whether a woman with a personality disorder and diabetes had capacity to make decisions about her diabetes management. The health professionals caring for her argued that she had fluctuating capacity because fluctuations in her diabetic control caused cognitive impairment and limited her capacity. Even when her blood sugar levels were in the normal range, her personality disorder meant that she was unable to weigh up risks and benefits when in an emotional state, but she could sometimes do so when calm.
The court held that capacity in relation to diabetes management required the ability understand, retain and use all the elements that influenced blood sugar levels in the body. A series of micro-decisions had to come together to make one overall macro-decision on diabetes management.
In Greenwich RLBC v CDM [2019] the court held that to have capacity the person had to be able to:
When viewed in this way the court held that while CDM might, at times, have capacity to make decisions about some of the micro elements, her personality disorder meant that she lacked capacity to be able to bring all these micro elements together into one macro-decision-making process necessary for safe diabetic management. The court concluded that she therefore lacked capacity to manage her diabetes and that this was unlikely to change given the enduring nature of her mental disorder. The judge in Greenwich RLBC v CDM [2019] emphasised that each case would turn on its unique facts with the relationship between the micro elements and the macro-decision being considered in each case.
Longitudinal decision making
In Cheshire West and Chester Council v PWK [2019] the court adopted a slightly different, and arguably more workable, approach to the challenges raised by what appears to be fluctuating capacity. The case concerned a man with autism, mild learning disabilities and a visual impairment. He was prone to anxiety, which in turn triggered irrational behaviour. He lived in a house with two-to-one supervision and involving a deprivation of liberty. The local authority sought declarations of incapacity in respect of a range of decisions, including his care, residence, use of social media and use of his Motability scheme car. His capacity was said to fluctuate depending on how anxious he was.
The court held that whenever the question of capacity arose, the court should start with a presumption of capacity, that capacity was a decision-specific concept and that a person lacked capacity if at the material time they were unable to make a decision for themselves because of an impairment of, or disturbance in the functioning of, the mind or brain (Mental Capacity Act 2005, sections 2 and 3).
In restating the requirements of the 2005 Act, the court did, however, make a distinction between the making of an isolated decision such as consent to a surgical procedure, or the making of a lasting power of attorney, and decisions that are ongoing and are taken regularly, often at short notice, and sometimes urgently, such as occurs in managing one's own affairs year on year. To have capacity to make these decisions requires the ability to adopt a longitudinal view to this continuous state of affairs whose demands were unpredictable and occasionally urgent.
In Cheshire West and Chester Council v PWK [2019] it was argued that finding a person lacked capacity because they were unable to take a longitudinal view of their ongoing affairs provided clarity for professionals caring for the person and allowed them to act in the best interests of the person by discharging their duties under the Mental Capacity Act, section 4.
Conclusion
The approach to fluctuating capacity adopted in Greenwich RLBC v CDM [2019] and Cheshire West and Chester Council v PWK [2019] provides a way forward for the Court of Protection and health professionals, including nurses, to assess a person's mental capacity.
In many cases nurses are assessing a person's ability to make a one-off decision where a temporary lack of capacity or fluctuating capacity can be overcome by delaying the need to make a decision until the person recovers and is able to make the decision themselves.
Fluctuating capacity for ongoing decisions can be much more challenging to manage but the longitudinal approach to repeated or macro-decisions set out in these cases should help nurses take a more considered approach to assessing decision-making capacity in such cases.