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Mental Capacity Act (MCA) practice guidance


Part 31 The Mental Capacity Act and the Mental Health Act

Code of Practice chapter 13

The Mental Health Act (MHA) is used to ensure that people who need treatment for serious mental disorder receive this treatment, even against their wishes, if there are sufficient risks to their own health or safety, or risks to the safety of other people. People are referred to as being ‘under section’ or ‘sectioned’ – usually this means being admitted to a psychiatric hospital.

There are situations where MHA is the most appropriate piece of legislation, situations where MCA is most suitable and situations where both are needed. It can be difficult to determine which law applies; and in addition the MHA and MCA Codes of Practice are further developed by case law.

MHA may be the suitable piece of legislation to use if:

  • the person needs to be deprived of their liberty to receive treatment for a mental disorder in a psychiatric unit
  • they need treatment for their mental disorder but do not lack capacity
  • they need treatment that can’t be provided under MCA – for example because of an Advance Decision
  • the risks are to other people and not to the person themselves. Principle 4 of MCA is clear that best interests decisions can only be made to address risks faced by the person who lacks capacity. MHA, in contrast, can be used to address risks to the person’s health or safety or the safety of other people.

The Mental Health Act:

  • doesn’t differentiate between people who have capacity and those who don’t – decisions are made about the nature or degree of someone’s mental disorder.
  • has no age limits
  • allows for people to be deprived of their liberty
  • overrules any Advance Decisions – however, if someone makes an Advance Decision refusing ECT (electro-convulsive therapy) this cannot be overruled. ECT can then only be given in an emergency to save someone’s life (MHA section 58A)
  • has a process to identify the person’s nearest relative who must be informed or consulted about many decisions and can veto some decisions
  • has clear criteria for all decisions taken under MHA; there are set assessment procedures, prescribed professional roles and set methods of recording decisions. There are rigorous review and appeal processes.

MCA covers decisions about all aspects of someone’s life while MHA only applies to assessment and treatment for mental disorder. This means that someone who is detained in hospital under MHA for treatment of their mental disorder will also need to be assessed under MCA to see if they have capacity to make decisions about treatment for physical illness.

The MCA applies to anyone who may have ‘an impairment of or disturbance in the functioning of the mind or brain.’ The MHA applies to ‘any disorder or disability of the mind.’ By excluding ‘the brain’ the MHA’s application is limited

If someone needs serious medical treatment for a physical illness their capacity to make this decision should be assessed. The process of assessment must include consultation with others. If there is no family or friends who can be consulted the person must be referred for Independent Mental Capacity Advocate support. (Part 16: Serious medical treatment)

Psychiatric units

When someone is ready to move on from in-patient treatment in a psychiatric unit some decisions may be made under the Mental Health Act, but most will be made under MCA. The person’s capacity to make decisions about future care options should be assessed, and if they lack capacity a best interests decision process should be followed. If the person is unbefriended and a decision is being made about a change of accommodation, a referral must be made for Independent Mental Capacity Advocate support. (Part 15: Independent Mental Capacity Advocates)

If someone is in psychiatric hospital and is seeking to leave or is refusing treatment they may be deprived of their liberty. They should be enabled to make their own decision about care and treatment, or a legal process needs to be followed to authorise their detention.

If someone is in hospital and is deprived of their liberty consider these questions.
1.    Does the person have capacity to make the decision about their care and treatment?
Yes – MCA does not apply. Use MHA or allow the person to leave/refuse treatment
No – MCA or MHA may apply. Consider the next question.

2.    Does the person meet the criteria for detention under MHA?
Yes – use MHA to detain for treatment of their mental disorder
No – use MCA Deprivation of Liberty Safeguards to authorise their detention.

Case law (GJ v The Foundation Trust [2009]) indicates that practitioners can’t choose whether to use MHA or MCA, even if they feel MCA DoLS would be less restrictive for the person. If someone is eligible for detention under MHA this law must be used. MCA DoLS can only be used for people who can’t be detained under MHA. This is different to some of the guidance in the Code of Practice. (Part 32: Deprivation of Liberty Safeguards)


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