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What are the Five Key Principles of the Mental Capacity Act?

Last updated on 5th December 2024

The Mental Capacity Act contains five key principles, which must be applied at any time when the Act is being used for individuals who lack capacity.

It is useful for practitioners if they consider the principles in chronological order; principles 1 to 3 support the process before or at the point in identifying if someone lacks capacity. Once this has been ascertained, principles 4 and 5 support the subsequent decision-making process.

Anyone who is involved in applying the Act must be aware of each principle, what it means and, vitally, how it applies in each individual’s own circumstances. Although the principles must be applied lawfully, every person who is being assessed for capacity must be treated as a unique individual; two people who live with the same illness, for example dementia, will experience it in completely different ways and so coming to a decision about application of the principles will not be the same and assumptions about individuals’ capacity should never be made.

The five key principles are:

  • Principle 1 – A presumption of capacity.
  • Principle 2 – The right to be supported when making decisions.
  • Principle 3 – An unwise decision cannot be seen as a wrong decision.
  • Principle 4 – Best interests must be at the heart of all decision making.
  • Principle 5 – Any intervention must be with the least restriction possible.

Principle 1 – A presumption of capacity

Every adult has a right to make their own decisions and they must be assumed to have the capacity to do so unless it is proven otherwise. Practitioners cannot assume that someone cannot make a decision for themselves just because they have a particular illness or disability, either physical or mental.

For example, if an individual has experienced a stroke, which has caused impairment to their ability to communicate, it is not acceptable to assume that this means that they lack capacity to make a decision, even if they might have some difficulties in communicating it.

Furthermore, in relation to this Principle, an assessment must only be sought if there is evidence to suggest that capacity might be an issue in terms of the decision that is being made.

When Principle 1 might be applied

  • When the individual’s behavior or circumstances cause doubt about their capacity to make a decision.
  • When someone is concerned about an individual’s capacity.
  • When the individual has a previous diagnosis of an impairment that might impact their capacity to make some decisions.
Lonely elderly woman lacking capacity

Principle 2 – The right to be supported when making decisions

All individuals must be given every opportunity in terms of support and information before it is decided that they cannot decide for themselves. This means that every effort to encourage and support people to make decisions for themselves must be given, for example giving information in an alternative format to make it easier to understand – this is often referred to as ‘maximizing capacity’.

Other examples of ways in which capacity might be maximized include:

  • Use of a signed language.
  • Use of an interpreter (for verbal information).
  • Use of a translator (for written information).
  • Use of communication aids such as picture cards.
  • Using an alternative communication format such as writing instead of speaking.
  • Meeting with an individual on several different occasions to assess or review capacity.
  • Changing a meeting’s location to one that is more suited to the individual’s needs.
  • Changing a meeting’s time to one that is more suited to the individual’s needs.

When Principle 2 might be applied

If a lack of capacity is established then the individual must still be involved, as far as possible, in any decision that are made on their behalf.

This will apply when:

  • Alternative forms of communication to ensure understanding have not been successful.
  • Consistent attempts to change locations or times of a meeting have not been successful.
  • Several meetings have all concluded that the individual’s level of capacity remains the same and that they are unable to make decisions on their own behalf.

Principle 2 Case study

Niko used to be a security guard working nightshifts at nightclubs and bars; after suffering a severe stroke however, he now requires full time care and supervision in a care home. Niko requires invasive surgery to fix a shunt in his brain to help alleviate pressure and reduce the likelihood of future strokes.

Initially the decision maker (DM) spoke to Niko about this decision around midday after a meeting at the care home; the DM suspected Niko lacked the capacity to make this decision as he presented as lethargic, withdrawn and disengaged.

However, the care home staff informed the DM that he is much more alert in the evenings as this was his routine for most of his working career. Upon returning out of hours, the DM was able to communicate more easily with Niko who was then able to make an informed decision.

​Meeting with the individual at a time when they are more alert (including out of ‘office hours’), or by using aids that help them understand or communicate, is taking practicable steps to help the person make a decision.

Principle 3 – An unwise decision cannot be seen as a wrong decision

Individuals must retain the right to make decisions, which others may deem eccentric or unwise. Such a decision must not be used as a reason to establish lack of capacity, as each person has their own beliefs and preferences and these may be in complete contrast to those who would otherwise determine them as lacking in capacity.

Principle 3 enables a person’s culture and individual characteristics to be taken into account when they are making decisions and it is clear that any decision that an individual makes, where they have capacity to do so, must be respected no matter how odd it may seem.

The Principle also enables health and social care professionals to consider if the individual has capacity but also to determine if the individual is under pressure from someone else to make a decision. For example, if an individual suddenly decided to change their will and leave all of their money to a person they almost never see but who has recently been to visit them, there may be cause for concern that the individual has been coerced into the decision.

However, it must be taken into account that when an individual repeatedly makes unwise decisions which leave them at significant risk or when they make a decision that is out of character, this should warrant further investigation.

Doctors and nurses having multi-disciplinary team meeting

When Principle 3 might be applied

The following are examples of decisions that must be respected in line with this Principle, as long as the individual retains capacity:

  • When an individual bases a decision on their religious beliefs, such as leaving money to a church or charity.
  • When an individual decides to wear clothing that might be considered socially inappropriate.
  • When an individual decides to stop taking some of their medication, which they do not believe is benefitting them.
  • When an individual takes up a hobby or activity that others believe is too risky for them.

Principle 3 Case Study

Ingrid is in the early stages of dementia and is currently receiving support in her own home from professional care workers. She has recently been meeting up with her 38-year-old grandson every week in a local restaurant and has been paying for lunch each time.

Her support worker is concerned that the grandson is exploiting Ingrid for money and free lunches and considers whether the situation needs to be formally investigated. Ingrid, however, is able to recognise the concerns that the support worker has and explains that her grandson is the only relative she has contact with and is happy to spend her disposable money on him as it maintains their contact and makes her feel like she still has a purpose and identity as a grandmother.

​Although this decision may appear unwise, and does cause some alarm, where the individual has capacity, their right to make unwise decisions should be protected.

Principle 4 – Best interests must be at the heart of all decision making

Decisions can only be made on behalf of an individual once it has been completely established that they lack capacity.

Any decision made on behalf of individuals who lack capacity must be done in their best interests. This means that what they would decide, if they had the capacity to do so should be the basis of the decision that is made. This can be very complex and depends on many factors that will maintain the individual’s wellbeing in a holistic manner, which means that all of their needs are taken into account.

It must also take into account the individual’s past wishes or actions, which includes an form of advance statement or directive that has been put into place.

When Principle 4 might be applied:

  • When it has been full established that the individual lacks capacity.
  • When it has been determined what is in the individual’s best interests.
  • When previous wishes, wants and factors relating to wellbeing have been established.

Principle 4 Case study

Robert has been involved in a road traffic accident as a pedestrian and has an internal bleed. He is unconscious at the point he arrives at the accident and emergency department, although his wife is with him.

When she is informed he has lost some blood and requires a blood transfusion, she protests and states that it goes against Robert’s firmly held beliefs as a Jehovah’s Witness as blood represents life and only God can give life. She states he would rather die if this is God’s wish.

It would save Robert’s life to receive blood, however this would cause him significant emotional and psychological distress as it goes against his religious beliefs; taking Robert’s religious beliefs into consideration, it would not be in his best interests to receive a blood transfusion. However, alternative forms of medical support could be explored.

Principle 5 – Any intervention must be with the least restriction possible

Any decision made on behalf of individuals who lack capacity must be done in a manner which is least restrictive to their freedom and their basic rights. Any intervention should be assessed given the circumstances of that particular case.

The decision make must, according to this Principle, consider all options available to them and always consider if there is a less restrictive option to the one proposed.

Sometimes, it is determined that what is in an individual’s best interests is not necessarily that which is the least restrictive. In such instances, consideration must be given to amendment to forms of care and support which are less restrictive but which do not put the individual at risk and which still ensure that their needs are met.

Nurse sat with elderly person before capacity assessment

When Principle 5 might be applied

  • When all options have been considered and the least restrictive one chosen.
  • When alternate forms of care have been considered if the least restrictive option may not be in the individual’s best interests for example if a person cannot go outside alone but to restrict them from doing this would be in deprivation of their liberty.

Principle 5 Case study

Ahmed has advanced stage dementia and has been found to lack the capacity to make a decision on his care and treatment; he currently requires full-time support and supervision. The care and treatment could be provided in a specialist dementia psychiatric unit, which would be highly restrictive.

The least restrictive option would be to receive care in his own home; however, this may not in the Ahmed’s best interests owing to concerns for his welfare and safety when his carers are not with him.

​The less restrictive option could be a nursing home, which allows him more freedom and a less restrictive regime than a psychiatric unit, but has more supervision than he would receive at home.

Best interests

The principle of always acting in a person’s best interests is a vital part of the Mental Capacity Act and should be pivotal in any action that it taken on behalf of someone who has been identified as lacking capacity.

The Act gives a checklist of key factors that must be taken into account when trying to determine what someone’s best interests will be.

Checking someone’s best interests, includes the following:

  • The wishes and feelings of the individual must be considered and these must be those, which are current and those, which may have been expressed prior to the loss of capacity.
  • All relevant circumstances must be taken into account, for example the individual’s mental and physical health, how long this might be likely to last, their age, if they would be normally be able to make a decision for themselves and if a recovery is likely in the near future.
  • If possible, the individual’s circumstances should be considered in terms of whether capacity to make a decision, which is non-urgent, can be postponed and made a time when their capacity might return. For example, someone experiencing a mental health crisis might not be able to make a decision in the immediate short term but they may be able to do so at a later time.
  • Discrimination should be avoided; best interests should not take into account a person’s appearance, their age, condition or their behaviour, as none of these are relevant to what is best for them. The opinions of others who know the individual well might be useful in determining their best interests but such opinions should never prejudice a decision against the individual.
  • The views of others should be taken into account if there is evidence that they have an interest in the welfare of the individual. The might include family, friends, carers and advocates.
  • If an individual has previously put their wishes and feelings into a written statement, these must be taken into account and respected wherever this is possible.
  • The individual must be encouraged to remain in control as far as this is possible and they must be involved in the decision-making process wherever they can.

There is no exhaustive list of factors to be taken into account when an individual’s best interests are being considered. However, those who are helping to ascertain what the individual’s best interests are must consider as many relevant factors as possible in order to bring about the best outcome.

Nurses discussing principles for the capacity act assessment for patient

Planning ahead – advance statements

A person’s best interests might be best determined by an ‘advance statement’ which is a written statement that outlines a person’s preferences, wishes, beliefs and values regarding their future care. Such a statement is important but it is not legally binding.

The aim of such a statement is to provide anyone who might make a decision in the individual’s best interests with a guide of what decision they would have made, had they have had the capacity to do so.

An advance statement can include any aspect of future health and social care, such as:

  • How their religious or spiritual beliefs might affect the care that they are given.
  • Where they would like to be cared for, such as at home or in a residential care setting.
  • How they would like to do things, such as showering instead of bathing and following a vegetarian diet.
  • Anything that concerns a practical issue such as caring for a pet or selling possessions.

Planning ahead – advance decisions

An advance decision, sometimes referred to, as a ‘living will’ is a legally binding decision that allows people who are aged 18 and over, whilst they are still capable, to refuse specified medical treatment for a time in the future when they may no longer be able to make such a decision.

An advance decision must remain valid and be applicable to an individual’s current circumstances; when it is so, healthcare professionals must follow the decision without question.

If the decision refuses life-sustaining treatment, it must:

  • Be in writing, signed and witnessed.
  • State clearly that the decision applies, even if it will put their life at risk.

Those individuals who make an advance decision should make their family, friends, carers and advocates know about it.

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About the author

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Megan Huziej

Megan has worked with CPD Online College since August 2020, she is in charge of content production, as well as planning, managing and delegating tasks. Megan works closely with our writers, voice artists, companies and individuals to create the most appropriate and relevant content as well as also using and managing SEO. She gained her Business Administration Level 3 qualification over the duration of being at CPD Online College as well. Outside of work Megan loves to venture to different places and eateries as well as spending quality time with friends and family.