This chapter outlines how the two acts work together for adults who have both mental health issues and lack mental capacity. It is adapted from the Mental Capacity Act 2005 Code of Practice and updated in relation to the Mental Health Act Code of Practice published in 2015. For further details please see the full guidance, as linked below.


Mental Capacity

Deprivation of Liberty Safeguards


Mental Capacity Act 2005 Code of Practice (2007)

Mental Health Act 1983: Code of Practice (2015)

This chapter was added to the APPP in October 2017.

1. Who does the Mental Health Act 1983 apply to?

The Mental Health Act 1983 (MHA), which was amended in 2007, provides ways of assessing, treating and caring for people who have a serious mental disorder that puts them or other people at risk. It sets out when:

  • people with mental disorders can be detained in hospital for assessment or treatment
  • people who are detained can be given treatment for their mental disorder without their consent (it also sets out the safeguards people must get in this situation), and
  • people with mental disorders can be made subject to guardianship or after-care, under supervision to protect them or other people.

Most of the MHA does not distinguish between people who have the mental capacity to make decisions and those who do not. Many people covered by the MHA have the capacity to make decisions for themselves.

Decision makers will need to decide whether to use either the MHA or MCA to meet the needs of people with mental health problems who lack capacity to make decisions about their own treatment. Where someone with a mental health disorder is subject to a Community Treatment Order (CTO) or Guardianship under the MHA, and lacks capacity, they may have a Deprivation of Liberty Safeguards in place; otherwise a person cannot be subject to the two frameworks at the same time.

See Appendix 1: Deciding whether the MHA and / or MCA will be available to be used – Flowchart

2. What are the Limits of the Mental Capacity Act?

The Mental Capacity Act 1983 (MCA) provides legal protection for people who care for or treat someone who lacks capacity. But they must follow the principles of the MCA (see Principles of the Mental Capacity Act, Mental Capacity) and may only take action that is in the person’s best interests. This applies to care or treatment for physical and mental conditions, and can apply to treatment for people with mental disorders, however serious those disorders are.

The MCA does have its limits, for example a practitioner who is restraining an adult in their care only has protection if the restraint is:

  • necessary to protect the person who lacks capacity from harm, and
  • in proportion to the likelihood and seriousness of that harm.

Initially the MCA was further limited as there was no protection under the MCA in relation to actions that deprived a person of their liberty. Deprivation of Liberty Safeguards, therefore, were introduced in 2007 as an amendment to the MCA to prevent breaches of the European Convention on Human Rights. It provides safeguards for people who lack the mental capacity specifically to consent to treatment or care in either a hospital or a care home that, in their own best interests, can only be provided in circumstances that amount to a deprivation of liberty, and where detention under the Mental Health Act 1983 is not appropriate for them at that time. See also Deprivation of Liberty Safeguards.

The MCA also does not allow giving treatment that goes against a valid and applicable advance decision to refuse treatment.

None of these restrictions apply to treatment for mental disorder given under the MHA – but other restrictions do.

3. When can a Person be Detained under the MHA?

A person can be detained for assessment under section 2 only if both the following criteria apply:

  • the person is suffering from a mental disorder of a nature or degree which warrants their detention in hospital for assessment (or for assessment followed by treatment) for at least a limited period, and
  • the person ought to be so detained in the interests of their own health or safety or with a view to the protection of others.

A person can be detained for treatment under section 3 only if all the following criteria apply:

  • the person is suffering from a mental disorder of a nature or degree which makes it appropriate for them to receive medical treatment in hospital;
  • it is necessary for the health or safety of the person or for the protection of other persons that they should receive such treatment and it cannot be provided unless the patient is detained under this section; and
  • appropriate medical treatment is available.

Decision makers should consider using the MHA if they are not sure it will be possible, or sufficient, to rely on the MCA. They do not have to ask the Court of Protection to rule that the MCA does not apply before using the MHA.

If a clinician believes that they can safely assess or treat a person under the MCA, they do not need to consider using the MHA. In this situation, it would be difficult to meet the requirements of the MHA anyway. Certain serious treatments under the MCA, such as non therapeutic sterilisation or withdrawal of artificial hydration or ventilation, must be referred to the Court of Protection for a final decision. Furthermore, a person should not be treated for a mental disorder or on a psychiatric ward under DoLS if they are likely to be treatable under the MHA

A person cannot be treated under the MHA unless they meet the relevant criteria for being detained.

4. How does the MCA apply to a Patient subject to Guardianship under the MHA?

Guardianship gives someone (usually a local authority social care department) the exclusive right to decide where a person should live – but in doing so they cannot deprive the person of their liberty (see Deprivation of Liberty Safeguards). The guardian can also require the person to attend for treatment, work, training or education at specific times and places, and they can demand that a doctor, approved social worker or another relevant person have access to the person wherever they live. Guardianship can apply whether or not the person has the capacity to make decisions about care and treatment. It does not give anyone the right to treat the person without their permission or to consent to treatment on their behalf.

Decision makers must never consider guardianship as a way to avoid applying the MCA.

5. Community Treatment Orders

A Community Treatment Order (CTO) is used where it is necessary for the patient’s health or safety or for the protection of others to continue to receive treatment after their discharge from hospital. It seeks to prevent the ‘revolving door’ scenario and the harm which could arise from relapse.

A key feature of the CTO framework is that it is suitable only where there is no reason to think that the patient will need further treatment as a detained inpatient for the time being, but where the responsible clinician needs to be able to recall the patient to hospital if necessary.

5.1 Deprivation of liberty while on a CTO, leave or subject to guardianship

Patients who are on a CTO or on leave, and who lack capacity to decide whether or not to consent to the arrangements required for their care or treatment, may occasionally need to be detained for further care or treatment for their mental disorder in circumstances in which recall to hospital for this purpose is not considered necessary. They might also need to be admitted to a care home or hospital because of physical health problems.

If they are to be detained in a care home, a DoL authorisation or Court of Protection order must be obtained. A court order of DoLS authorisation (used for care home placements in the community) for a deprivation of liberty can exist alongside a CTO or leave of absence, provided there is no conflict with the conditions of the CTO or leave set by the patient’s responsible clinician.

If they are to be detained in a hospital for further treatment for mental disorder (whether or not they will also receive treatment for physical health problems), they should be recalled to be treated under the Act. The MCA cannot be used to authorise the deprivation of their liberty.

6. How does the Mental Capacity Act affect People covered by the Mental Health Act?

There is no reason to assume a person lacks capacity to make their own decisions just because they are subject under the MHA to:

  • detention;
  • guardianship, or
  • after-care under supervision.

People who lack capacity to make specific decisions are still protected by the MCA even if they are subject to the MHA (this includes people who are subject to the MHA as a result of court proceedings). But there are four important exceptions:

  • if someone is liable to be detained under the MHA, decision makers cannot normally rely on the MCA to give mental health treatment or make decisions about that treatment on someone’s behalf;
  • if somebody can be given mental health treatment without their consent because they are liable to be detained under the MHA, they can also be given mental health treatment that goes against an advance decision to refuse treatment;
  • if a person is subject to guardianship, the guardian has the exclusive right to take certain decisions, including where the person is to live; and
  • Independent Mental Capacity Advocates (IMCAs) do not have to be involved in decisions about serious medical treatment or accommodation, if those decisions are made under the MHA (see Independent Mental Capacity Advocacy Service).

7. What are the Implications for People who need Treatment for a Mental Disorder?

Subject to certain conditions, the MHA allows doctors to give patients who are detained treatment for mental disorders without their consent – whether or not they have the capacity to give that consent.

Where Part 4 of the MHA applies, the MCA cannot be used to give medical treatment for a mental disorder to patients who lack capacity to consent. Nor can anyone else, like an attorney or a deputy, use the MCA to give consent for that treatment. This is because Part 4 of the MHA already allows clinicians, if they comply with the relevant rules, to give patients medical treatment for mental disorder even though they lack the capacity to consent. In this context, medical treatment includes nursing and care, habilitation and rehabilitation under medical supervision.

But clinicians treating people for mental disorder under the MHA cannot simply ignore a person’s capacity to consent to treatment. As a matter of good practice (and in some cases in order to comply with the MHA) they will always need to assess and record:

  • whether patients have capacity to consent to treatment, and
  • if so, whether they have consented to or refused that treatment.

8. How does the Mental Health Act affect Advance Decisions to Refuse Treatment?

The MHA does not affect a person’s advance decision to refuse treatment, unless the person can be treated for mental disorder without their consent. In this situation healthcare staff can treat patients for their mental disorder, even if they have made an advance decision to refuse such treatment.

But even then healthcare staff must treat a valid and applicable advance decision as they would a decision made by a person with capacity at the time they are asked to consent to treatment. For example, they should consider whether they could use a different type of treatment which the patient has not refused in advance. If healthcare staff do not follow an advance decision, they should record in the patient’s notes why they have chosen not to follow it.

Even if a patient is being treated without their consent under Part 4 of the MHA, an advance decision to refuse other forms of treatment is still valid. Being subject to guardianship or after-care under supervision does not affect an advance decision in any way.

9. Does the MHA affect the Duties of Attorneys and Deputies?

In general, the MHA does not affect the powers of attorneys and deputies. But there are two exceptions:

  • they will not be able to give consent on a patient’s behalf for treatment under Part 4 of the MHA, where the patient is liable to be detained under the Act; and
  • they will not be able to take decisions:
    • about where a person subject to guardianship should live, or
    • that conflict with decisions that a guardian has a legal right to make.

Being subject to the MHA does not stop patients creating new Lasting Powers of Attorney (if they have the capacity to do so), or does it stop the Court of Protection from appointing a deputy for them.

Attorneys and deputies are able to exercise patients’ rights under the MHA on their behalf, if they have the relevant authority. In particular, some personal health and welfare attorneys and deputies may be able to apply to the First Tier Tribunal for the patient’s discharge from detention, guardianship or aftercare under supervision.

The MHA also gives various rights to a patient’s nearest relative (see MCA CoP for further information).

It is good practice for clinicians and others involved in the assessment or treatment of patients under the MHA to try to find out if the person has an attorney or deputy.

10. Does the MHA affect when Independent Mental Capacity Advocates must be instructed?

10.1 Independent Mental Capacity Advocates

See also Independent Mental Capacity Advocacy Service.

As referenced in Section 6, How does the Mental Capacity Act affect people covered by the Mental Health Act? there is no duty to instruct an IMCA for decisions about serious medical treatment which is to be given under the MHA. Nor is there a duty to do so in respect of a move into accommodation, or a change of accommodation, if the person in question is to be required to live in it because of an obligation under the MHA. That obligation might be a condition of leave of absence or conditional discharge from hospital or a requirement imposed by a guardian or a supervisor.

However, the rules for instructing an IMCA for patients subject to the MHA who might undergo serious medical treatment not related to their mental disorder are the same as for any other patient.

The duty to instruct an IMCA would also apply as normal if accommodation is being planned as part of the after-care under section 117 of the MHA following the person’s discharge (see 117 Aftercare).

10.2 Independent Mental Health Advocates

Independent mental health advocacy services provide an additional safeguard for patients who are subject to the MHA. Independent Mental Health Advocates (IMHAs) are specialist advocates who are trained specifically to work within the framework of the Act and enable patients to participate in decision-making, for example, by encouraging them to express their views and supporting them to communicate their views. They are commissioned by the relevant local authority. IMHAs should be independent of any person who has been professionally involved in the patient’s medical treatment.

IMHA services do not replace any other advocacy and support services that are available to patients, such as independent mental capacity advocates (IMCAs) or representatives for patients who lack capacity, but are intended to operate in harmony with those services.

Appendix 1: Deciding whether the Mental Health Act or Mental Capacity Act will be available to be Used – Flowchart

Click here to view Deciding whether the MHA or MCA will be available to be Used: Flowchart

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