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- Mental capacity and mental illness - The Mental Capacity Act 2005
Mental capacity and mental illness
The Mental Capacity Act 2005
This information explains what mental capacity is and how the Mental Capacity Act works. It also explains who can make decisions for you if you lose capacity. This information is for people who are 18 or over and affected by mental illness in England. It is also for their loved ones, carers and anyone interested in this subject.
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Frequently asked Q's
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- Having mental capacity means that you can make important decisions for yourself. Lacking mental capacity means you cannot understand or make certain decisions for yourself.
- The Mental Capacity Act (MCA) is the law that protects you if you lack capacity. It is different from the Mental Health Act (MHA).
- Being detained under the MHA, being unwell or having a mental illness does not in itself mean that you lack capacity. Nor does making unwise choices.
- Mental capacity is assessed through tests that look at your ability to make a specific decision at a specific time. You may lack mental capacity for a short or longer period of time.
- The MCA sets out who can make decisions for you if you lack capacity.
- If someone makes a decision for you because you lack capacity, it needs to be in your ‘best interests’.
- If you have been assessed as lacking capacity and you do not agree, there are things you can do. An independent mental capacity advocate may be able to help you.
- You can make a Lasting Power of Attorney (LPA) or advance decision if you are worried about losing capacity.
- If you lose capacity and do not have an LPA, the Court of Protection might appoint a deputy.
- You might not have created an LPA and there might be no deputy. You can still get support managing your welfare benefits from an appointee, or other support.
- If you are in a care setting and lack capacity, deprivation of liberty safeguards may be used. This is to keep you safe.
- Carers are also protected under the MCA.
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The Mental Capacity Act says mental capacity means you can make your own decisions. This is assessed by whether you can:
- understand all the information you need to make that decision,
- use or weigh up that information,
- remember that information, and
- communicate your decision to someone else.
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The Mental Capacity Act 2005 (MCA) is a law about adults and mental capacity.
The Act will cover you if you are:
- 16 or older, and
- live in England and Wales.
The MCA is there to do the following:
- Define what mental capacity is.
- Help you to make decisions for yourself if you lack mental capacity. Your friends, family or carer can help you to make a decision. If you do not have any support, you can get an independent mental capacity advocate to help you.
- Give you the option to make decisions about your future. Such as your care preferences and who will manage your money. But, you will have to make these decisions when you have mental capacity.
- Say who can make certain decisions for you. Any decision made for you must be in your best interest.
- Protect you if you lack capacity. The MCA has made it a criminal offence to harm or neglect someone who lacks capacity. If someone gets convicted of this offence, they could get a fine or go to prison.
What are the 5 key principles of the Mental Capacity Act?
The MCA is based on 5 rules called ‘key principles.’ The key principles are below.
- You must be treated as if you have capacity, unless there is evidence that you do not.
- Before medical professionals decide you do not have capacity, you must be supported to make your own decisions. An example might be giving you the information in a different way and trying explain it differently. You might have other symptoms which are causing you to lack capacity. The medical team should treat those first. They can assess your capacity again after your symptoms are treated.
- If you have mental capacity, you have a right to make decisions that other people may think are unwise.
- If you do not have mental capacity, anything done for you must be in your best interests.
- If you lack mental capacity, anyone making decisions for you must use the least restrictive option available. This means they must choose options that have the least effect on your basic rights and freedoms.
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The Mental Capacity Act 2005 (MCA) and the Mental Health Act 1983 (MHA) are different laws.
Under the MHA you can be detained in hospital for assessment and treatment if you have a mental disorder and you are very unwell.
Detention in hospital is used as a last resort. It is used when someone is a serious risk to themselves or others because of their mental disorder. This does not automatically mean you lack mental capacity to make decisions.
Under the MHA you can be forced to have treatment whether you agree to it or not. So, even if you have capacity, you can be given treatment for your mental disorder against your will.
You can find more information about the Mental Health Act on our webpage.
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If your carer or healthcare professional thinks you lack capacity, they will assess your ability to decide. First they must check if you can make the decision for yourself with their support.
Anyone who assesses your mental capacity should have the skills needed to communicate with you. A professional can help the assessor if they need support.
Generally, a capacity assessment should be related to a specific decision that you are making. This is because you might have capacity to make one decision but lack capacity to make another. For example, you might be able to decide what treatment you want. But, you might not be able make one about a financial matter.
You will be assessed on the following 4 points to see if you can:
- understand the information you need to make the decision,
- remember and use that information again,
- understand what will happen when you make the decision, or
- communicate your decision in any way, such as talking, sign language or squeezing someone’s hand.
The test has 2 stages.
Stage1:
there must be proof that you have an illness or injury that affects the way your mind works, andStage 2:
if you do, it affects you so much that you are unable to make a specific decision at a certain time.Stage 2 will only apply if you have been given enough support to try and make the decision for yourself. But you are still unable to.
Health professionals should only assess your mental capacity using this test. They cannot base their decision on your age, appearance or diagnosis alone.
What is an illness or injury that affects the way my brain works?
An illness or injury that affects how my brain works could be things like:
- conditions associated with some forms of mental illness,
- dementia,
- significant learning disabilities,
- the long-term effects of brain damage,
- physical or medical conditions that cause confusion, drowsiness or loss of consciousness,
- the symptoms of alcohol or drug use,
- delirium, and
- concussion following a head injury.
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Losing capacity may be temporary. For example, you could live with a mental illness which sometimes gets worse. This may affect your ability to make decisions at certain times. This is called ‘fluctuating capacity’.
For example, if you live with bipolar disorder, you may lack the capacity to make financial decisions if you have an episode of mania. You may be able to understand and remember the information. You may also be able to say what you want. But you might not understand what could happen after you decide.
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John lives with schizophrenia. He believes that his doctors want to harm him. John has a large blood clot that needs to be removed immediately. Without an operation, he may die.
John is given information about his operation and what could happen without treatment. John is also given information about the treatment they want to give him and what to expect. He decides not to have the treatment.
John can understand the information, remember the information, and tell his healthcare team his decision. But John believes that his risk of dying is higher if he has the operation because he believes that the doctors are trying to harm him. This belief is not true. So, professionals decide John is not mentally capable of weighing up risk. They do this after following the capacity test as laid out in the Mental Capacity Act.
John is assessed as lacking mental capacity to make this decision to refuse treatment. An emergency application is made to the court. They agree John lacks capacity, and it is in his best interest to have the operation. The operation is a success and John recovers well.
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Anyone who makes a decision for you must follow the 5 key principles of the Mental Capacity Act. You can read about these in the ‘What is the Mental Capacity Act (MCA)?’ section above.
They must follow the Mental Capacity Act Code of Practice and only make decisions that are in your best interests.
The Mental Capacity Act Code of Practice is a guide that explains how to apply the law when making decisions for people who may lack capacity. It helps professionals, carers, and families understand their responsibilities and how to act in someone’s best interests. You can access the mental capacity act code of practice here.What sort of decisions can be made for me?
Most decisions can be made for you. Common decisions that may be made are:
- financial decisions,
- medical treatment, and
- day-to-day support.
But there are some decisions or actions that can never be decided for you. These include:
- voting,
- placing a child for adoption, and
- getting married or having a civil partnership.
Who will make the decision for me?
Different people may need to make decisions for you at different times.
Your main decision maker for a specific decision is most likely to be one of the following people:
- Your carer or a loved one for day-to-day decisions
- Your doctor or a healthcare professional will make decisions about your medical treatment.
- Your solicitor for legal decisions.
- Your attorney under a Lasting Power of Attorney (LPA). For more information see ‘What is a Lasting Power of Attorney?’ below
- Your court appointed deputy. For more information see ‘What is the Court of Protection and the Office of the Public Guardian?’ below.
Your decision maker has a duty to consult with other people involved in your care before a decision is made. They will make a ‘best interest’ decision for you.
What are my best interests?
Your best interests are individual to you. They are based on different things. To decide what your ‘best interests’ are the person making the decision needs to think about:
- your views and beliefs about things like religion, politics, and morals,
- what is written on your advance statement,
- what is written on your advance decision,
- if you will ever be able to make the decision for yourself, and if so, when are you able to make the decision, and
- any other important factors that are specific to the situation.
The decision should not be based only on your appearance, age, mental health diagnosis or your behaviour.
The decision maker must allow and encourage you to be involved with the decision that affects you.
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You must be treated as if you have capacity unless there is evidence that you do not.
Your capacity might be assessed, and it might be decided that you lack capacity to make a particular decision. You might disagree with this.
To try and solve this disagreement you could try the following:
- Talk to your assessor,
- Ask for a second opinion,
- Use a mediation service, or
- Apply to the Court of Protection – See the ‘What is the Court of Protection and the Office of the Public Guardian?’ section below
The Ministry of Justice provide an online directory of mediators. The service is provided on a fixed-fee basis.
You can access the Ministry of Justice online directory here.
Who can help me to challenge the decision?
You can get help from your family or friends. Or, you may be able to get help from an independent mental capacity advocate (IMCAs).
IMCAs support people who have capacity problems. They can help when no one else suitable such as a friend, carer, or LPA is available. IMCAs can help you understand your rights and help you get your voice heard.
You can use an NHS advocate if you are making a complaint an NHS service. They are free to use and independent from the NHS.
You can find more information on our webpages about:
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If you are worried that you might lose mental capacity in the future, there are things that you can do.
You can create:- a Lasting Power of Attorney - see the ‘What is a Lasting Power of Attorney (LPA)?’ section below, and
- an advanced statement or advanced decision.
What are advanced statements and advanced decisions?
You can make an advanced statement or advanced decision if you have mental capacity at the time.
Advance statements
An advance statement is a general preference about your treatment and care.
It is not legally binding. But medical professionals should still make a practical effort to follow your wishes.
Advanced decisions
You can use an advanced decision to refuse specific medical treatment if you lose the mental capacity to decide for yourself.
Advanced decisions are legally binding. But Health professionals do not have to follow an advance decision if you are in hospital under the Mental Health Act.
An advanced decision cannot be used for anything else.
You can find out more about 'Advance statements and advance decisions - Planning your future care' on our webpage.
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The Court of Protection is a specialist court that makes decisions for people who lack capacity.
The Office of the Public Guardian protects people who cannot make decisions for themselves. It oversees attorneys under Lasting Powers of Attorney and court-appointed deputies. It tries to make sure they act in the best interests of people who lack capacity.
What can the Court of Protection (CoP) do?
The CoP can protect you if you lack capacity. It can:
- decide if you have the mental capacity to make a decision,
- decide if a Lasting Power of Attorney (LPA) can be registered - see the ‘What is a Lasting Power of Attorney (LPA)?' section below,
- appoint deputies to make decisions in your best interests - see the ‘What is the Court of Protection and the Office of the Public Guardian?’ section below,
- give people permission to make one-off decisions in your best interests,
- make decisions in difficult cases,
- handle urgent or emergency cases,
- decide if Deprivation of Liberty safeguards (DOLs) should be used – see the ‘What are Deprivation of Liberty Safeguards (DoLS)?’ section below, and
- remove deputies or attorneys who have not carried out their role properly.
What can the Office of the Public Guardian (OPG) do?
The OPG has different jobs including:
- registering Lasting Power of Attorneys (LPA’s),
- keeping a public register of deputies and LPA’s,
- supervising deputies and ensuring they are following the Mental Capacity Act,
- taking action if there are concerns about an LPA or deputy, and
- looking into reports of abuse against LPA’s or deputies.
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A Lasting Power of Attorney (LPA) is a legal document that gives one or more people authority over your affairs. The law that deals with LPAs is The Mental Capacity Act 2005.
There are 2 types of LPA:
- health and welfare decisions, and
- financial decisions.
If you create an LPA, you are known as the donor. The person you appoint is known as the attorney.
You must have mental capacity to make an LPA.
If you are making a property and financial affairs LPA, then you can choose when it starts. It can start at the time of making it. Or, you can choose for it to only start if you lose capacity.
If you are making a health and welfare LPA it can only start if you lose capacity.
After LPA’s are signed, they need to be registered with the Office of the Public Guardian (OPG) .
You can read more about LPAs here
What powers does an attorney have under an LPA for financial decisions?
Your attorney’s powers will usually include, but are not limited to, things like:
- running your bank and savings accounts,
- making or selling investments,
- dealing with your benefits,
- paying your bills, and
- buying or selling your house or other property.
You can read more about being a financial attorney here
If you have not made an LPA and lack capacity, you can still get help with welfare benefits. A trusted person can become your appointee and manage your benefits for you.
For more details about appointees, see the section below headed: ‘Can I get help with my benefits without an LPA or court-appointed deputy?’
What powers does an attorney have under an LPA for health and welfare?
Health and welfare decisions can include:
- day-to-day care,
- medical treatment,
- complaints about your care and treatment, or
- where you should live
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You might lack capacity to make financial or welfare decisions. But you might not have created a Lasting Power of Attorney.
Someone can apply to the Court of Protection to become your deputy. This would give them the power to manage your financial affairs or to make a welfare decision. There is a cost involved in this process.
If the Court of Protection agrees to appoint a deputy, they will issue a court order. The court order says what powers the deputy has.
The law that deals with deputy orders is The Mental Capacity Act 2005.
There are 2 types of deputy order:
- property and financial affairs deputy, and
- personal welfare deputy.
The court normally only issues health and welfare deputy orders in extreme circumstances.
You can read more about deputy orders here.
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You can get support with your benefits and help dealing with the Department for Work and Pensions (DWP). You can do this even if you do not have a Lasting power of attorney (LPA) or a deputy.
There are different types of help available, depending on your support needs.
What is an ‘appointee’?
An appointee is someone who manages your welfare benefits if you are mentally incapable or severely disabled.
An appointee can:
- Sign benefit forms for you,
- Tell the DWP about changes that may affect your benefits, and
- Receive your benefits, and make sure they are spent in your best interests.
The person wanting to be an appointee must tell the DWP why they think the role is needed. The DWP will then assess your situation and make sure the appointee is suitable for the role.
An appointee is usually someone you know. If no one is suitable, an organisation like your local authority can act as a ‘corporate appointee’. They may choose a staff member who works closely with you to manage your benefits.
An appointee can only manage your benefits. They cannot manage other financial affairs. You will need a court-appointed deputy for this.
You cannot have an appointee if you already have a lasting power of attorney who has authority over your finances. This is the same if you have a court-appointed deputy. They will automatically take this role.
You can read more about appointees and how to become one here.What are ‘additional support markers’?
If you can manage your own benefits but need extra support, the DWP can add an ‘additional support marker.’
An additional support marker is a note that tells the DWP you need extra help.
It helps the DWP understand your needs and support you the best they can.
You will need to speak to the DWP directly to add a support marker. You can tell them what your needs are.
What is an ‘official representative’?
You may find DWP processes difficult to understand, even if you can still manage your own money. If so, you can give consent for someone to talk to the DWP for you. This person is called an ‘official representative.’
An official representative does not take full control of your benefits. They can help you:
- make a claim for benefits,
- check the progress of an application,
- ask the DWP about any decisions they have made, and
- speak to the DWP if you want to review your benefits or make an appeal.
To add someone as an official representative you need to contact the DWP. You can:
- contact your job coach,
- speak to the DWP on the phone, or
- send an online message in your journal in your universal credit account.
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DoLS stands for 'deprivation of liberty'. ‘Deprivation of liberty’ means loss of freedom. They can sometimes be used if you are in a hospital or care home and lack mental capacity.
The care home or hospital must get permission from a supervisory body first. This is required before they can lawfully deprive you of your liberty. The supervisory body will usually be a primary care trust or a local authority.
DoLS can only be used when:
- it is in your own best interests to protect you from harm,
- it is needed because of the likelihood and seriousness of harm, and
- if there is no other way to keep you safe.
There are safeguards in place to make sure:
- you get a representative to support you with all things to do with DoLS. Such as your right to challenge your DoLS through the Court of Protection,
- you are supported by an independent mental capacity advocate if you want more support and you meet certain criteria, and
- the DoLS is reviewed.
DoLS cannot be used if you are detained in hospital under the Mental Health Act.
You can learn more about DoLS here.
Are DoLS changing and what are Liberty Protection Safeguards (LPSs)?
The Mental Capacity (Amendment) Act 2019 says that the Liberty Protection Safeguards (LPSs) will replace DoLS in the future.
The government have yet to provide a date when this will happen. We will update this information when LPSs replace DoLS.
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If you are a carer for someone who lacks capacity you may be asked to be a decision maker. You may have questions about what your rights are and how it will affect you.
You can contact the Office of Public Guardian with questions about becoming a decision maker and your rights. Their details can be found in the ‘Useful contacts’ section below.
Carers UK provides advice for carers, including advice on the Mental Capacity Act. They have online resources, an email support service and a helpline. Their details can be found in the ‘Useful contacts’ section below.
The Carers Trust do not advise on the Mental Capacity Act, but they do offer advice on supporting yourself as a carer. Their details can also be found below in the ‘Useful contact’ section below.
How does the Mental Capacity Act protect me?
The Mental Capacity Act protects carers and healthcare professionals. If someone you care for is assessed as lacking capacity, you may be asked to make a decision for them.
You are usually not legally responsible for the outcome of that decision if it was made in their best interest.
I do not agree with a decision that is being made about the person I care for. What can I do?
Often more than one person is involved with decisions that affect someone who lacks mental capacity. This means that disagreements can happen.
See the ‘I do not agree that I lack mental capacity. What can I do?’ section above for information about how to challenge a decision.
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Office of the Public Guardian (OPG)
The Office of the Public Guardian (OPG) protects people in England and Wales who may not have the mental capacity to make certain decisions for themselves.Phone: 0300 456 0300.
Address: PO Box 16185, Birmingham, B2 2WH
Email: customerservices@publicguardian.gov.uk
Website: www.gov.uk/government/organisations/office-of-the-public-guardian
Court of Protection
Make decisions on financial or welfare matters for people who lack mental capacity.Phone: 0300 456 4600
Address: PO Box 70185, First Avenue House, 42-49 High Holborn,
London, WC1A 9JA
Email: courtofprotectionenquiries@justice.gov.uk
Website: www.gov.uk/courts-tribunals/court-of-protection
The British Institute of Human Rights
Their guide explains what the 16 human rights are and how they impact treatment options and services of those with mental illness, including those who lack capacity.Website: www.bihr.org.uk/get-informed/what-rights-do-i-have
Carers UK
Provides support for carers on a range of different subjects, including the Mental Capacity Act.Helpline: 0808 808 7777
Helpline Email: advice@carersuk.org
General Email: info@carersuk.org
Address: 20 Great Dover Street, London SE1 4LX
Website: www.carersuk.org/help-and-advice/helpline-and-other-supportCarers Trust
Provides advice for carers, including advice on respite, benefits and general well-being.Email: info@carers.org
Phone to find local carers network: 0300 772 9600
Website: https://carers.org
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© Rethink Mental Illness 2026
Last updated August 2025
Next update August 2028, subject to any changes
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