Mental Capacity Act summary guidance

Guidance for staff on the application of the Mental Capacity Act 2005 Code of Practice.

Version: 2
Date published: September 2025
Review due: September 2028

Introduction

This guidance has been produced for frontline staff, with the intention of summarising and clarifying the key principles of the Mental Capacity Act and the considerations you should make when completing a Mental Capacity Assessment.

This guidance is not exhaustive and should be read alongside the Mental Capacity Act 2005 Code of Practice (Department for Constitutional Affairs, 2007). That document contains details around the legal status of the Code, Lasting Powers of Attorney, the Court of Protection, Deprivation of Liberty Safeguards, and Best Interests decisions, which are not within the scope of this guidance.

You should refer to your own organisation’s policies and procedures, alongside this guidance, and use your own organisation’s mental capacity assessment form, if you have one.

Your responsibilities

The Mental Capacity Act 2005 Code of Practice provides guidance to anyone who is working with adults who may lack capacity to make decisions, and particularly decisions about their care and treatment. It is intended for use by a wide range of staff, including (but not limited to):

• healthcare staff, such as doctors, nurses, dentists, and paramedics;
• social care staff, such as social workers and care managers;
• district and borough council staff, such as housing workers;
• police;
• care workers, including care home staff and domiciliary care workers;
• voluntary sector workers who are providing a service to the adult.

What is mental capacity?

Mental capacity is defined as the ability to make a specific decision, at the time that the decision needs to be made.

This can include ‘daily life’ decisions, such as what to wear, or daily routines, or more ‘complex’ decisions which have more significant consequences. This could include decisions around medical treatments or planning a will.

Statutory principles

There are five key principles underpinning the Mental Capacity Act. It’s important to keep these principals in mind, whenever you are undertaking work relating to the Mental Capacity Act.

1. You must assume that adults have capacity to make their own decisions, unless it is established that they don’t have capacity.
2. Before deciding that a person doesn’t have capacity to make a decision, you must take reasonable steps to support them to be able to make decisions for themselves; this could include using different forms of communication or supporting them to learn new skills. This, however, may not apply in an emergency situation if immediate action is required.
3. If an adult makes an ‘unwise decision’ it does not automatically mean that they don’t have capacity. You will need to explore the reasons for their decision.
4. Any decision made under the Mental Capacity Act must be made in the best interests of the adult.
5. Any decision made under the Mental Capacity Act must be done so in the least restrictive way possible, respecting their rights and freedoms.

Helping adults to make decisions

Before deciding that an adult doesn’t have capacity to make a specific decision, it’s important that you work with them, to support them to make the decision, if they can.

To do this, you need to consider the following:

• Do you know the best way to communicate with the adult? Discuss this with those who know the adult best. You may need to communicate pictorially or engage the help of an interpreter.
• Are they comfortable in the environment? Think about how you can make them feel more comfortable, including reducing distractions and respecting their privacy.
• Are you speaking with them at a good time? Some people are more alert in the mornings or evenings. If they are taking medication, does it make them drowsy for a time after taking it?
• Would they benefit from the presence of a friend or family member? You may also wish to consider whether they would benefit from an advocate.

Assessing capacity

Once you have made the decision to assess an adult’s mental capacity, you need to consider the following three questions, which constitute the mental capacity ‘test’:  

1. Is the adult unable to make the decision in question, at the time it needs to be made?
2. Does the adult have an impairment of the mind or brain, or is there some sort of disturbance affecting the way their mind or brain works? The impairment could be a temporary or permanent impairment and can include (but not limited to) mental illness, dementia, learning disabilities, medical conditions causing confusion, or symptoms of drug or alcohol use.
3. Is the adult’s inability to make the specified decision as a result of the identified impairment or disturbance?

If the answer to all three question is ‘yes’, then the adult will lack capacity to make the specified decision.

To help you judge the above test, you need to consider the following questions:

• Does the adult understand the decision that needs to be made, and why?
• Do they understand the consequence of the decision?
• Can they understand, retain, use, and weigh up relevant information?
• Can they communicate their decision?
• If the decision required is a ‘complex’ decision, do you need to involve other professionals and take a multi-agency approach? This could be their GP or healthcare specialist.

Whilst we know that capacity assessments are generally related to specific decisions, where capacity assessments relate to an ongoing condition and/or an ongoing decision to be made, you should repeat the capacity assessment at regular intervals, including whenever a care plan is developed or reviewed. Undertaking capacity assessments in this way provides clear evidence and recording of baseline information at different points, which can then be taken into account or referenced for subsequent capacity assessments for the same decision.

Fluctuating, decisional and executive capacity

It’s important to be aware that there are a number of factors which can affect capacity. Some people have fluctuating or temporary capacity.

This means that their capacity can be affected by temporary factors, such as acute illness, severe pain, the effects of medication, or experiencing trauma or grief. In these situations, if possible, you should put off making the decision until they are better able to engage in the process.

You may also hear people talking of ‘decisional’ versus ‘executive’ capacity or functioning. Whilst the Mental Capacity Act Code of Practice doesn’t specifically reference these terms, Community Care has some key pointers about these terms (Executive functioning and the Mental Capacity Act 2005: points for practice, 2023).

In some cases, adults may have the capacity to make decisions about their life, but lack the capacity, or functioning, to carry out the necessary tasks related to the decision. In these cases, it’s important to consider:

• What practicable support can you offer to support the adult to execute the decision?
• Is the adult being realistic about their executive functioning, or are they overestimating their ability to execute their decision?
• What does past behaviour tell you? Do they have a history of not following-through with important decisions and actions?

Much like fluctuating capacity, sometimes executive capacity or functioning can be impacted by temporary or extenuating factors. This could include in cases where an adult’s use of alcohol impacts their ability to complete tasks related to a decision, even where they have decisional capacity. It’s important to work out what support the adult might need to execute actions in these cases, and to ensure you are taking a multi-agency approach and seeking support from organisations such as drug and alcohol services, where appropriate.

Making 'unwise' decisions

Sometimes, we might be uncomfortable with a decision that an adult has made, because we consider it to be ‘unwise’ and to place them at ongoing or increased risk.

It’s important to remember, though, that we all have our own beliefs, values, and preferences, and we cannot assume that somebody lacks capacity just because we think they are making a poor, or ‘unwise’, decision. If you think somebody is making an unwise decision, but you assess them to have capacity to make that decision, they have a right to make that decision for themselves, as long as they are aware of the risks. However, you may want to reassess capacity if you feel that someone is repeatedly making unwise decisions; is acting out of character; may be under undue duress or coercion; there appears to be a potential issue with their executive functioning or capacity; and/or the risk changes or increases.

Recording your decision

It is good practice for staff to keep a written record of the steps they have taken to assess mental capacity for all decisions, including ‘daily life’ decisions. This is particularly important, though, for mental capacity assessments made in relation to ‘complex’ decisions.

Details of the assessment should be recorded in:

• healthcare clinical notes;
• legal client files, in the case of solicitor or police involvement;
• care plans.

Your organisation may have their own format for recording mental capacity assessments. If this is the case, you should use these formats to record the steps you have taken in assessing capacity. If your organisation does not have their own format, though, you could consider a format similar to the example below:

• Record of mental capacity assessment (PDF, 109KB)