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Mental capacity act

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.

See the separate Consent To Treatment (Mental Capacity and Mental Health Legislation), Consent To Treatment In Children (Mental Capacity and Mental Health Legislation) and Compulsory Hospitalisation articles.

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What is the Mental Capacity Act?1

The Mental Capacity Act (2005) provides a statutory framework to empower and protect vulnerable people who are not able to make their own decisions. It makes it clear who can take decisions, in which situations, and how they should go about this. The Mental Capacity Act enables people to plan ahead for a time when they may lose capacity. The Act replaces previous statutory schemes for Enduring Powers of Attorney and Court of Protection Receivers with reformed and updated schemes. The Mental Capacity Act applies to people aged 16 and over.

One review of the experiences of adults lacking capacity and their carers found that2 :

  • The legislation provided mechanisms for decision-making which were seen as useful, but there were negative experiences.

  • Decision-making did not always seem to follow the legislative principles.

  • Awareness of the legislation was limited.

Principles of the Mental Capacity Act3 4

The Mental Capacity Act is underpinned by five key principles:

  • A presumption of capacity: every adult has the right to make their own decisions and must be assumed to have capacity to do so unless it is proved otherwise.

  • The right for individuals to be supported to make their own decisions: people must be given all appropriate help before anyone concludes that they cannot make their own decisions.

  • That individuals must retain the right to make what might be seen as eccentric or unwise decisions.

  • Best interests: anything done for or on behalf of people without capacity must be in their best interests.

  • Least restrictive intervention: anything done for or on behalf of people without capacity should be the least restrictive of their basic rights and freedoms.

Assessment of mental capacity is specific for each individual decision at any particular time. People are considered to lack capacity if they have an impairment which causes them to be unable to make a specific decision. The person should be able to understand, retain and weigh the information provided and communicate their decision.

Independent mental capacity advocates should be appointed to represent people who lack capacity and face serious decisions with no one to be an advocate for them. The possible causes of incapacity are wide-ranging and include dementia, acute confusion, depression, psychotic illness, distress or emotional disturbance. No specific diagnosis should be assumed to imply incapacity.

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Purposes of the Act3

The Mental Capacity Act deals with the assessment of a person's capacity and acts by carers of those who lack capacity.

Assessing lack of capacity

  • The Mental Capacity Act sets out a single clear test for assessing whether a person lacks capacity to take a particular decision at a particular time.

  • It is a 'decision-specific' test. No one can be labelled 'incapable' as a result of a particular medical condition or diagnosis.

  • A lack of capacity cannot be established merely by reference to a person's age, appearance, or any condition or aspect of a person's behaviour which might lead others to make unjustified assumptions about capacity.

  • To test if the person has capacity:

    • Does the person have an impairment of the mind or brain, or a disturbance of mental function?

    • If so, does that impairment or disturbance mean that the person is unable to make the decision in question at the time it needs to be made?

  • To have capacity to make a decision, someone must be able to:

    • Understand the information relevant to the decision.

    • Retain the information.

    • Use that information as part of the process of making the decision.

    • Communicate their decision either by talking, signing, or any other means.

Best interests

  • Everything that is done for or on behalf of a person who lacks capacity must be in that person's best interests.

  • The Mental Capacity Act provides a checklist of factors that decision-makers must work through in deciding what is in a person's best interests.

  • A person can put their own wishes and feelings into a written statement if they so wish, which the person making the determination must consider.

  • Carers and family members have a right to be consulted.

  • All decisions must be made in the best interest of that person:

    • Involve the person who lacks capacity.

    • Be aware of the person's wishes and feelings.

    • Consult with others who are involved in the care of the person.

    • Do not make assumptions based solely on the person's age, appearance, condition or behaviour.

    • Consider whether the person is likely to regain capacity to make the decision in the future.

Acts in connection with care or treatment

  • Section 5 of the Mental Capacity Act clarifies that where a person is providing care or treatment for someone who lacks capacity then the person can provide the care without incurring legal liability. The key will be proper assessment of capacity and best interests.

  • This covers actions that would otherwise result in a civil wrong or crime if someone has to interfere with the person's body or property in the ordinary course of caring. For example, by giving an injection or by using the person's money to buy items for them.

  • The Bill introduces a new criminal offence of ill treatment or neglect of a person who lacks capacity. A person found guilty of such an offence may be liable to imprisonment for a term of up to five years.

Restraint or deprivation of liberty

  • Section 6 of the Mental Capacity Act defines restraint as the use or threat of force where an incapacitated person resists, and any restriction of liberty or movement whether or not the person resists.

  • Restraint is only permitted if the person using it reasonably believes it is necessary to prevent harm to the incapacitated person, and if the restraint used is proportionate to the likelihood and seriousness of the harm.

  • Section 6(5) makes it clear that an act depriving a person of his or her liberty cannot be an act to which section 5 provides any protection.

Advance care planning

See also the separate Advance Care Planning article.

  • The Mental Capacity Act introduced advance care planning, giving a person the right to make decisions about their healthcare treatment in the future, for a time when they may no longer have the capacity to make such decisions for themself.

  • Advance care planning replace 'advance directives', which were made prior to the Mental Capacity Act. Advance directives may still be valid and applicable under the Mental Capacity Act but no new advance directives can now be made.

  • Advance care planning can only be made by people aged 18 years or older and considered to have mental capacity.

  • Under advance care planning, any treatment can be refused, except for those actions needed to keep a person comfortable - eg, warmth, shelter and offering food or water by mouth.

  • Wishes to have certain treatments may be expressed in advance which must be taken into account; however, they do not have to be followed.

  • An advance care plan carries the same weight as decisions made by a person with capacity and must be followed. Therefore, best interests do not apply.

  • Advance care plans may be verbal, except those about life-sustaining treatment which must be in writing and signed by the patient and a witness, and include a statement that the decision is to apply even if life is at risk.

  • The advance care plan becomes invalid if the decision is withdrawn or amended when the person still had capacity (or even if there have been any actions suggesting they changed their mind after making the advance decision), or if there are 'lasting powers of attorney' with powers to make the same decision after the advance decision was made.

  • The advance care plan must apply to the specific circumstance in question.

  • Going against a valid and applicable advance care plan can result in claims for battery or criminal charges of assault.

Lasting powers of attorney

  • The Mental Capacity Act allows a person to appoint an attorney to act on their behalf if they should lose capacity in the future.

  • The Act allows people to let an attorney make financial, property, health and welfare decisions.

  • The designated attorney must be aged 18 years or older.

  • The lasting powers of attorney only come into force once the person has lost capacity and the lasting powers of attorney must be registered with the Office of the Public Guardian5 .

  • The person making the lasting powers of attorney must have capacity when they sign a written document confirming the powers and limitations of the powers of attorney.

Independent Mental Capacity Advocate (IMCA)

  • An IMCA is someone appointed to support a person who lacks capacity but has no one to speak for them. The IMCA makes representations about the person's wishes, feelings, beliefs and values at the same time as bringing to the attention of the decision-maker all factors that are relevant to the decision. The IMCA can challenge the decision-maker on behalf of the person lacking capacity if necessary.

  • An IMCA must be involved in the following situations and where the person lacks capacity and has no relative, friend or unpaid carer:

    • An NHS body is proposing:

      • Serious medical treatment.

      • A stay of more than 28 days in hospital or eight weeks in a care home.

      • Change to a person's accommodation to another hospital for more than 28 days or more than eight weeks in a care home.

    • A local authority is proposing:

      • To change or to provide residential or supported accommodation for more than eight weeks.

  • An IMCA may also be involved in:

    • Accommodation reviews where there are concerns about the suitability of the placement, where the Local Authority or NHS has arranged the original accommodation, the person lacks capacity, and there is no other person appropriate to consult.

    • Adult protection cases where protective measures are being put in place in relation to the protection of a vulnerable adult from abuse, and where the person lacks capacity.

    • Where the person who lacks capacity is abusing another person.

  • Involvement of an IMCA is not necessary:

    • If any treatment needs to be provided as a matter of urgency.

    • If the person lacking capacity would be made homeless unless they were admitted to a care home.

    • In accommodation reviews or adult protection cases where there is already appropriate family support or where an advocate is currently involved.

Parameters for research

  • Research involving, or in relation to, a person lacking capacity may be lawfully carried out if an 'appropriate body' (normally a Research Ethics Committee) agrees that the research is safe, relates to the person's condition and cannot be done as effectively using people who have mental capacity. The research must produce a benefit to the person that outweighs any risk or burden.

  • Alternatively, if it is to derive new scientific knowledge, it must be of minimal risk to the person and be carried out with minimal intrusion or interference with their rights.

  • Carers or nominated third parties must be consulted and agree that the person would want to join an approved research project. If the person shows any signs of resistance or indicates in any way that he or she does not wish to take part, the person must be withdrawn from the project immediately.

  • Transitional regulations will cover research started before the Act where the person originally had capacity to consent but later lost capacity before the end of the project.

Court appointed deputies

  • The Mental Capacity Act provides for a system of court-appointed deputies to replace the previous system of receivership in the Court of Protection.

  • Deputies will be able to take decisions on welfare, healthcare and financial matters as authorised by the Court but will not be able to refuse consent to life-sustaining treatment. They will only be appointed if the Court cannot make a one-off decision to resolve the issues.

  • The Act creates two new public bodies to support the statutory framework, both of which will be designed around the needs of those who lack capacity.

Court of Protection

  • The Court has jurisdiction relating to the whole Act and is the final arbiter for capacity matters. It has its own procedures and nominated judges.

  • The Public Guardian and their staff supervise deputies appointed by the Court and provide information to help the Court make decisions. They also work together with other agencies, such as the police and social services, to respond to any concerns raised about the way in which an attorney or deputy is operating.

  • A Public Guardian Board scrutinises and reviews the way in which the Public Guardian discharges their functions. The Public Guardian is required to produce an Annual Report about the discharge of their functions.

Deprivation of liberty safeguards6 7

  • The aim of the deprivation of liberty safeguards is to provide legal protection for those vulnerable adults who are not detained under the amended Mental Health Act 1983 but are restricted in their freedom due to their inability to consent to care or accept treatment.

  • The deprivation of liberty safeguards (an amendment of the Mental Capacity Act 2005) came into effect on 1 April 2009 and cover mentally incapacitated adults in hospitals, as well as those in care homes registered under the Care Standards Act 2000.

  • The safeguards apply to anyone aged 18 years and over:

    • Who has a mental disorder or disability of the mind - eg, dementia or a profound learning disability.

    • Who lacks the capacity to give informed consent to the arrangements made for their care and/or treatment; and

    • For whom deprivation of liberty is considered after an independent assessment to be necessary in their best interests to protect them from harm.

  • Whenever a hospital or care home identifies that a person who lacks capacity is being, or risks being, deprived of their liberty, they must apply to a 'supervisory body' for authorisation of deprivation of liberty:

    • When a person is in a care home, the supervisory body will be the relevant Local Authority.

    • When the person is in a hospital, this will be the relevant Clinical Commissioning Group (CCG).

  • The Mental Capacity Act 2005 will not permit someone being deprived of their liberty without such an authorisation (unless it is a consequence of following a decision of the Court of Protection on a personal welfare question).

  • Doctors are eligible to undertake a mental health assessment as part of these procedures, provided they are three years post-registration and they must have undertaken the deprivation of liberty safeguards Mental Health Assessors training programme made available by the Royal College of Psychiatrists.

  • This work is not part of Essential Services for GPs, and the British Medical Association's (BMA) Professional Fees Committee advises doctors to undertake this work only if they have agreed the level and payment arrangements for the work in advance.

  • Responsibility for payment lies with the CCG or Local Social Services Authority (LSSA) according to whether the person is in hospital or a Registered Home at the time of the assessment.

Further reading and references

  1. Dunlop C, Sorinmade O; Embedding the Mental Capacity Act 2005 in clinical practice: an audit review. Psychiatr Bull (2014). 2014 Dec;38(6):291-3. doi: 10.1192/pb.bp.114.046870.
  2. Wilson S; Mental capacity legislation in the UK: systematic review of the experiences of adults lacking capacity and their carers. BJPsych Bull. 2017 Oct;41(5):260-266. doi: 10.1192/pb.bp.116.055160.
  3. Mental Capacity Act 2005.
  4. Nicholson TR, Cutter W, Hotopf M; Assessing mental capacity: the Mental Capacity Act. BMJ. 2008 Feb 9;336(7639):322-5.
  5. The Office of the Public Guardian
  6. Mental Capacity and Deprivation of Liberty – an update on reform; British Geriatric Society. May 2017 - last updated April 2018
  7. Mental Capacity Act (MCA) resource; Social Care Institute for Excellence, last updated July 2020

Article History

The information on this page is written and peer reviewed by qualified clinicians.

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