Here, we look at some of the key ethical and legal issues related to making health decisions on behalf of adults who lack capacity. The law in this area differs across the UK; detailed information and guidance can be found in our core ethics guidance.

How to proceed if the individual lacks the capacity to consent?

We have seen previously in this toolkit the importance of respecting autonomous choices and how this is expressed in the requirement to seek informed consent from patients. If patient consent renders an intervention legally and ethically acceptable, how are we to proceed where the individual lacks the capacity to consent? (Where the individual is a child, or young person aged under 16, and lacks competence to make a decision, those with parental responsibility can consent on their behalf). Where adults aged 16 and over lack capacity other people will have to make the decision for them.

Although you will not directly be involved in assessing capacity or making ‘best interests’ (‘benefit’ in Scotland) decisions, demographic changes mean that, throughout your future career, many of you will be looking after adults who may be suffering from some degree of cognitive impairment.

Food for thought

Why does capacity matter?

Our right to determine what happens to our bodies is straightforwardly vital to our wellbeing. In doctor-patient relationships this right is sometimes translated as the moral obligation on doctors to show respect for persons and their autonomous choices. This right, and its corresponding obligation, are at the moral centre of medical practice.

Respect for persons includes both respect for their choices and a concern for their welfare. When someone becomes incapable of making self-governing decisions, their decision-making rights give way and concern for their welfare comes to the fore. A decision that someone lacks capacity is therefore a serious one, involving the loss of fundamental human freedoms. In contrast, a failure to identify that someone lacks the capacity for autonomous choice can also expose them to serious harms.

What is mental capacity and why is it important?

In addition to being voluntary and informed, autonomous decisions require the possession of sufficient mental capacity. In law all people aged 16 and over are presumed to have the capacity to make decisions on their own behalf. Legally, capacity refers straightforwardly to our ability to take actions or make decisions that influence our lives. A decision that adults lack capacity is obviously a significant one. It strips us of our right to control our lives in relation to the decision in question.

When does an adult patient lack capacity?

An adult is deemed to lack decision-making capacity if, at the time the decision needs to be made, they are unable to make or communicate the decision because of some form of impairment of the mind or brain (or, in Scotland, a mental illness, physical disability, or neurological impairment).

This can include factors such as mental illness or the cognitive decline associated with Alzheimer’s disease. It can also refer to short term factors such as extreme intoxication by drugs or alcohol.

How much capacity is enough?

Although there will be times when it is obvious that someone lacks capacity – they may be unconscious – in the majority of cases, people retain the capacity to make some decisions.

One of the really challenging questions is the extent to which a person’s capacity must be impaired before they lose their right to make a decision.

There is no straightforward answer to this. UK law takes a functional and decision-specific approach. It asks if the individual has the capacity to make a specific decision at a specific time, not whether they have the ability to make decisions generally. Ordinarily, the more complicated or serious the decision, the greater the evidence of capacity required to make it and the more thorough and searching the assessment of capacity.

Who should assess capacity?

There is a presumption in law that all people over the age of 16 have the capacity to make decisions relating to their life. Where there are doubts about capacity and consent to medical treatment is required, the healthcare professional proposing the treatment needs to decide whether the patient has the capacity to consent.

In some circumstances, such as where there are genuine doubts about capacity and the decision is a serious one, expert advice from a psychiatrist or psychologist with particular experience in assessing capacity should be sought. Overall responsibility remains, however, with the healthcare professional proposing the treatment.

How can treatment lawfully be provided to adults who lack the capacity to consent?

There are a number of ways in which treatment can be provided lawfully to adults who lack the capacity to make the decision.

• Where an adult patient has no one with legal authority to make a decision on their behalf, treatment can be provided where it is both necessary, and in the patient’s best interests (benefit in Scotland) – a ‘best interests’/’benefit’ decision.
• In England, Wales, and Scotland where the person has previously nominated someone to make the decision – a welfare attorney.
• In England and Wales where the Court of Protection has appointed a deputy to make the decision, and in Scotland a Sheriff-appointed guardian, or intervener
• Under mental health legislation.

What is a ‘best interests’/'benefit' test?

All decisions taken on behalf of someone who lacks capacity must be taken in their best interests (benefit in Scotland). Case law has established that when assessing an individual’s interests, decision makers must look at their welfare in the broadest sense. This must extend beyond medical factors to incorporate social and psychological dimensions of wellbeing.

As part of the assessment process the Supreme Court has made clear that the decision maker must make a reasonable effort to put themselves in the place of the patient and ask what their attitude to the proposed treatment would be.

Factors that need to be taken into account when making a best interests/benefit assessment include the following:

• the extent of the person’s ability to participate in the decision;
• the likelihood that the person will regain capacity in sufficient time to be able to decide personally;
• the person’s past and present wishes and feelings;
• their beliefs or values where they would be relevant to the decision; and
• the benefits and burdens of the decision.

An important part of any best interests/benefit assessment is, where possible, a discussion with those close to the individual in order to try and establish those things that were important to the patient, and which may have an impact on the decision.

Advance decisions refusing treatment

Adults with capacity can refuse specified treatment for a time in the future when they may lose capacity. This is called an advance decision to refuse treatment (ADRT), or advance statement in Scotland. These are sometimes known colloquially as a ‘living will’. Patients can only refuse treatment by means of an advance decision, they cannot commission treatment in advance.

When they meet the legal criteria, and are applicable to the circumstances that have arisen, advance decisions are likely to be legally binding.