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Mental capacity
Mental capacity is about being able to make your own decisions.
It is decision and time specific. We all make decisions every day, and most of us are able to make these ourselves. Sometimes, we may lack capacity to make a big decision. But this doesn't always mean we are unable to make smaller decisions such as what to wear each day.
Capacity is decision and time specific
Watch this film to hear doctor-in-training, Gee Hothi, explain what capacity is, and who can assess capacity
64. You must work on the presumption that every adult patient has the capacity to make decisions about their care, and to decide whether to agree to, or refuse, an examination, investigation or treatment. You must only regard a patient as lacking capacity once it is clear that, having been given all appropriate help and support, they cannot understand, retain, use or weigh up the information needed to make that decision, or communicate their wishes.
65. You must not assume that a patient lacks capacity to make a decision solely because of their age, disability, appearance, behaviour, medical condition (including mental illness), their beliefs, their apparent inability to communicate, or the fact that they make a decision that you disagree with.
(Consent: patients and doctors making decisions together)
When seeing patients, you must start with the presumption that every adult patient has the capacity to make decisions about their care.
If in doubt, assess your patient’s capacity in line with the relevant national law and our guidance.
Always assess a patient’s capacity to make a particular decision at the time it needs to be made. Don’t assume that because a patient lacks capacity to make a decision on a particular occasion, they lack capacity to make any decisions at all now or in the future. Requirements can differ from country to country but by following the principles in our Consent guidance you’ll always be in line with the law. Always record your actions and decision clearly.
Myth busters
Sometimes people make assumptions about whether a patient has capacity. When assessing capacity, always start with assuming that the person does have capacity. Below are some incorrect assumptions.
If someone...

- is in severe pain they don’t have capacity
- is unable to communicate verbally they don’t have capacity
- has dementia they don’t have capacity
- has alcohol dependence they don’t have capacity
- makes a decision you disagree with they don’t have capacity
- has a learning disability they don't have capacity
- has a mental disorder they don't have capacity
- is within the criminal justice system/prison they don't have capacity
- have a terminal illness they don't have capacity
Related guidance
Consent: patients and doctors making decisions together
Paragraphs 64–65
Learning points
- Begin with the presumption of capacity.
- Capacity is decision and time specific.
- You can help maximise a patient's ability to make a certain decision.
21. You should check whether the patient needs any additional support to understand information, to communicate their wishes or to make a decision. You should bear in mind that some barriers to understanding and communication may not be obvious; for example, a patient may have unspoken anxieties, or may be affected by pain or other underlying problems. You must make sure, wherever practical, that arrangements are made to give the patient any necessary support.
(Consent: patients and doctors making decisions together)
It is a doctor’s duty to help patients maximise their ability to have capacity and therefore be involved in their own healthcare.
Below are a few examples of why someone may struggle at each stage of assessing capacity and some possible ways which may help them and result in them having capacity.
My patient doesn't understand English
- Get an interpreter
- Provide written information in their language
- Use confidential telephone translation service as approved by the trust
My patient is deaf
- Use an appropriate interpreter
The terminology used is too complicated
- Use simple language
- Use diagrams to illustrate point
- Allocate more time to consultation
My patient is under the influence of drugs or alcohol, impairing their ability to retain
- Wait until they are no longer under the influence if possible (ie non urgent situation)
My patient has mild dementia – some people are unable to retain information when given at certain times of the day, and if not given enough time
- If the patient can’t tell you, ask those who know them what time of day is best for a consultation
- Revisit the information on several occasions
- Give written information so they can go over at home
My patient is emotional as they have just been given some difficult information and are unable to weigh up decision
- Give them more time
- Revisit the information
- Help them to categorise their thoughts, eg for and against
My patient is unable to verbally communicate
- Give them paper or a computer for written communication
- Get someone who can translate sign language
This tool will help you decide what to do when you doubt your patient's capacity to make decisions about their care.

Related guidance
Consent: patients and doctors making decisions together
Paragraphs 66–70
What to consider if your patient lacks capacity
If you assess that your patient lacks capacity to make the relevant decisions, you must make decisions about their care based on what would be ‘of overall benefit’ (in their best interests). When making these decisions there are a range of legal requirements laid down in national mental capacity laws and codes which you must take into account.
Some of the requirements are essential procedural steps, for example completing a capacity certificate (Scotland), or authorising a ‘deprivation of liberty’ in some treatment situations.
There are also statutory decision-making principles, safeguards and good practice requirements set out in these national laws or codes, which you must incorporate into your usual practice. For example, the importance you should attach to exploring a patient’s previous wishes, preferences, values and beliefs; how you communicate with and involve a patient’s family or others close to the patient; your approach to obtaining second opinions; and how you work with the healthcare team and multi-agency teams to inform and to implement decisions.
Our Consent guidance sets out professional standards of practice in this area which take account of the legal requirements in national mental capacity laws and codes across England, Wales, Scotland and Northern Ireland.* You can be confident that the standards in our guidance are consistent with the legal obligations that apply in the country where you practise. Of course it’s important to seek advice, in case of any uncertainty about the current legal position, as the law in this area can be complex. We are currently updating the Consent guidance to ensure it continues to reflect current law, as well as providing doctors with more practical advice on applying the guidance.
Put your learning into practice...

Mental capacity: Support to make end of life care decisions

Mental capacity: Supporting patients to make decisions about their care
