Assessing best interests when patients can't consent to treatment

How to make a best interests assessment.

If a patient requires medical treatment but lacks the capacity to consent to it, the treating doctors may need to make a decision based on their best interests.

This article examines the law and guidance in England and Wales. In Scotland, the relevant legislation is the Adults with Incapacity (Scotland) Act 2000 and the relevant Code of Practice. In Northern Ireland the Mental Capacity Act (Northern Ireland) 2016 received Royal Assent in May 2016 and will govern this area once fully in force. Members are welcome to contact us for further advice on assessing the best interests of patients in Scotland and Northern Ireland.

Assessment of capacity is set out in the Mental Capacity Act (MCA) 2005 and its accompanying Code of Practice. These provide a framework for caring for or treating people 16-years old or over in England and Wales who lack the ability to make decisions for themselves.

Legal framework

Cases where patients may lack capacity but need medical treatment can be very challenging and we have previously issued advice on how to assess a patient's capacity which can be read in conjunction with this guidance. This covered some key points, including that, decisions made or action taken for or on behalf of a person who lacks mental capacity must be done in their best interests.

The concept of best interests and how to assess this can be confusing and it is important to note that 'best interests' is not defined by the MCA or the accompanying Code of Practice. Instead the legislation provides broad principles and a framework to enable individuals to work through a process then reach a decision tailored to the particular situation.

Taking an individual approach

The individualised approach is well summarised in the judgement of Aintree University Hospitals NHS Foundation Trust v James [2013] UKSC 67. Recognising the difficulty in making these individual decisions the Supreme Court explained:

"The most that can be said, therefore, is that in considering the best interests of this particular patient at this particular time, decision-makers must look at his welfare in the widest sense, not just medical but social and psychological; they must consider the nature of the medical treatment in question, what it involves and its prospects of success; they must consider what the outcome of that treatment for the patient is likely to be; they must try and put themselves in the place of the individual patient and ask what his attitude to the treatment is or would be likely to be; and they must consult others who are looking after him or interested in his welfare, in particular for their view of what his attitude would be."

The decision therefore must be the one which the healthcare professional reasonably believes is right for the individual patient in question. It is not an application simply of what might be felt generally to be the best medical approach.

Define the decision

Section 4 of the MCA sets out a checklist of common but not exclusive factors which must be considered when making a best interest assessment and Chapter 5 of the Code of Practice expands on this checklist. However, before working through the checklist below, it's important to define the decision to be made along with the various options and choices available.

Chapter 6 of the Code of Practice explains that, 'In emergencies, it will almost always be in the person's best interests to give urgent treatment without delay.' With a key exception to this being that a valid, applicable advance decision to such treatment is in place (see below).

Best interests checklist

The below checklist sets out the steps to take when arriving at a best interests decision:

  • You must not make assumptions about someone's best interests based simply on age, appearance, condition or behaviour.
  • You should consider all relevant circumstances when working out someone's best interests. This will vary from case to case and further guidance is available on page 74 of the Code of Practice.
  • You should make every effort to encourage and enable the person who lacks capacity to take part in the decision making.
  • You should consider if there is a possibility that the person will regain the capacity to make a particular decision. If so, then it may be possible to put off the decision until this occurs if it is not urgent.
  • You should take into account the person's past and present wishes and feelings, beliefs and values and factor these into the decision making process.
  • The views of others who are close to the person who lacks capacity should be considered, including those caring for and interested in the patient's welfare, as well as the views of any attorney or deputy, and anyone named by the patient to be consulted - while being mindful of the patient's right to confidentiality.
  • Special considerations apply to decisions about life-sustaining treatment.

In complex decisions where it is difficult to conclude which course of action will lead to the best outcome for the patient it can be helpful to draft a pros and cons list for each of the options. This can help to identify the preferred outcome and to identify the risks and benefits of each option, their likelihood, and seriousness or importance to the patient.


There are also two important exceptions to when the best interest principles will apply:

  1. When the patient has previously made an advanced decision (AD) to decline medical treatment. Provided the AD is valid and applicable to the situation and there is no evidence that the patient has since changed their mind, it should be respected even if it leads to a course of action, or inaction, not considered to be in their best interests.
  2. Certain situations when a patient who lacks capacity might be involved in research. Chapter 11 of the Code of Practice goes into further detail about the circumstances surrounding this exception.

Record keeping

It is important to keep clear records of the process by which the patient's best interests were established, including steps taken to involve the patient. It should be clear from the record how the decision about the person's best interests were reached and what the reasons for making that decision were. Records can include:

  • what circumstances were considered
  • what values, wishes and beliefs have been accounted for
  • which other individuals have been consulted as part of the assessment, and what their views and observations were
  • other aspects of the case you considered when going through this process.

Careful documentation will ensure there is a clear picture of the patient's care and it can also aid you if you are called on to justify your decision. It may well be valuable to set out a list of the pros and cons, with the risks and benefits, and what has been done to reduce any risks, together with the conclusion as to what option is in the patient's best interests and why.

Some reassurance

While the principles and process may seem daunting section 4(9), is clear that if you act or make a decision in the reasonable belief it is in the best interests of the person who lacks capacity, applying the checklist described above, you will have complied with the best interests principle set out in the Act.

You must, however, be able to show that it was reasonable for you to conclude that you were acting in the patient's best interests at the time. Chapter 6 of the Code or Practice provides more details on the protection offered by the Act for those providing care.

Having a best interests meeting, involving those caring for the patient, family members, and those interested in patient's welfare, may be very useful. If some are unable to attend, they may be able to participate virtually or supply information in writing. A written record should be made of the meeting.

Remember to get further direction from your trust legal team or the MDU if you are uncertain how to proceed in individual cases.

This page was correct at publication on 08/03/2021. Any guidance is intended as general guidance for members only. If you are a member and need specific advice relating to your own circumstances, please contact one of our advisers.

Dr Ellie Mein MDU medico-legal adviser

by Dr Ellie Mein Medico-legal adviser


Ellie joined the MDU as a medico-legal adviser in 2013. Prior to this she worked as an ophthalmologist before completing her Graduate Diploma in Law in Birmingham.