Mental Capacity Act Myth Busters

Dementia Care
September 30, 2021

True or false, only a doctor can assess someone’s capacity? Still unsure? Don’t worry Rachel Griffiths, MBE, dispels 10 common myths surrounding the Mental Capacity Act.

You can download the PDF version below to share with your team or print it out and have it on your desk! 

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Alternatively, you can read the 10 common myths and facts below:


If Jim lacks capacity for a decision, his next of kin must make it.


The term ‘next of kin’ is often used, but it doesn’t have any meaning in law – and gives no powers to make decisions for any other adult. When a decision needs to be made, and someone lacks capacity to make that decision, for example to consent to or refuse treatment, medication or care, the decision must be made in the person’s best interests.

However, anyone aged 18 or over, with capacity to understand what they’re doing, can give someone they trust – usually a relative or friend – decision-making powers, by creating Lasting Powers of Attorney, known as LPAs. These can be of two kinds – for financial and property decisions, and for health and welfare decisions. Any of us can make either, or both, of these. For more information, see here.



If I’m worried about a decision someone is making, they’ve got to convince me they have capacity to make it.


The person doesn’t have to prove anything! Nobody ever has to prove they have capacity; the first principle of the Mental Capacity Act is that everyone is presumed to have capacity unless there is reason to think that they don’t. Before anyone can act on the basis that someone lacks capacity, they must show that it is likelier than not that the person really does lack capacity for that decision. For how to assess capacity, see here.



Millie has been diagnosed with dementia, so that means she lacks capacity to make any of her own decisions.


Mental capacity is ‘decision and time specific’: this means, can the person make this particular decision at the time it needs to be made. Lots of people with mild dementia, or a learning disability, might be able to make many, or even all, the decisions that they need to make.

They may need extra help to understand what is involved, and what their options are – for example, to be told more than once, or in simple words, or using pictures.

And someone who has had a brain injury in an accident or from a stroke may be likely to regain capacity quite quickly. You must never say that everyone with a certain diagnosis, or who looks a certain way, lacks capacity. Millie might lack the capacity to make complicated decisions, but she may be able to decide between different cakes. For more on supporting people to make their own decisions, see here.



Only a doctor can assess someone’s capacity.


The person who needs to assess if someone lacks capacity for a decision is the person who will take that decision instead, and act on it, if the person can’t do this for themselves. It will sometimes be a doctor, but different people might assess someone’s capacity at different times, especially if their capacity is likely to vary.

A nurse assesses Jaz’s capacity to consent to having a dressing changed, and, if she decides he does not (because he cannot remember he has a diabetic ulcer) then she is likely to decide that, at this time, he cannot make this decision. She is the person who will be protected under the Mental Capacity Act if she decides it is in his best interests to have the dressing changed, and then does it, as tactfully and with as much pain relief as possible.

Front line care staff are protected under the Mental Capacity Act if they are following a care plan based on assessments of capacity that are highly unlikely to change, for example because the person has progressive dementia. But all the same they need to be aware that capacity is assessed by asking, ‘can this person make this decision at the time they need to make it?’



If a person we support is making an unwise decision, we must always let them do what they want, even if it puts them in danger.


Everyone does have the right to make a decision that other people think is ‘unwise or eccentric’, provided they have the capacity to understand what they are doing. If a person might come to real harm by a decision or action that they do not have the capacity for, then other people must act in their best interests to stop them.

Piet has dementia; he gets upset sometimes because he thinks he is late for school, so he tries to cross the busy road outside his care home to find the primary school that once stood there. Staff decide he lacks capacity because he can’t remember about the heavy traffic on what used to be a quiet lane; they make a decision in his best interests, and gently stop him crossing the road, by distracting him with a cup of tea. They are protected by the Mental Capacity Act, because they reasonably believe Piet lacks capacity, and they reasonably believe that their actions are in his best interests.



You shouldn’t help someone to understand their options when assessing their capacity; you would be helping them to cheat.


The Mental Capacity Act says that, except in an emergency, we must do everything possible to help someone make their own decision. We might pick a time and place where the person will be most calm and rested; we might ask trusted relatives or friends to help the person; we might use pictures or objects to help them understand their options. The NICE guidance on supporting people with making decisions is here.



An Advance Decision to Refuse Treatment must be signed by the doctor; and a person can use it to get expensive treatment that other people can’t get; and they can use it to make staff help them die. (Three myths in one!)


The purpose of an Advance Decision to Refuse Treatment is that anyone aged 18 or older, with the capacity to know what they are doing, can decide to refuse in advance a specific medical treatment if they are ever offered it, in the future, at a time when they lack capacity to consent to it. If properly made, it has the same effect as the person standing there with capacity and saying, ‘No thanks, Doc.’

A doctor isn’t involved in making it, because it’s so personal (though they need to know it exists, to obey it.) It can’t be used to force any doctors to give any treatment; it can’t be used to refuse being taken to live in a care home, or to be given personal care; and it can’t be used to force anyone to help you die (and anyway assisted dying is completely unlawful in this country). To find out all about Advance Decisions to Refuse Treatment, see here.



The Mental Capacity Act only applies to people with dementia.


The Mental Capacity Act protects the rights of anybody aged 16 and over who might lack mental capacity due to some condition in their mind or brain that makes them unable to take a decision at the time it needs to be made. This might happen with lots of conditions, such as learning disability, brain injury after a stroke or an accident, or the effects of drugs and alcohol. It applies to any adult who gets knocked off their bike and taken unconscious into A&E; when they come round, they can make their own decisions, but until then, the Mental Capacity Act protects the doctors and nurses who make decisions in the person’s best interests. See Mental Capacity Act Code of Practice for more information.



If someone has powers under a Lasting Power of Attorney (LPA) for health and welfare decisions, they can’t make decisions that apply in medical settings or care homes; we can simply tell them what we have decided to do.


By giving powers under an LPA for health and welfare to someone you trust, you are giving them the power to ‘stand in your shoes’ to accept or refuse any intervention that is offered, if, at some time, a decision needs making, and you lack capacity to make it yourself.

The only difference is that an individual with capacity can make an unwise decision and take the consequences – we can deliberately decide to spend too much on shoes or drive too fast – but anyone using LPA powers to make a decision has to put the person’s well-being at the heart of their decisions and must always decide in their best interests.

The person making an LPA can personalise it by giving some powers and withholding others, so staff in health and social care may need to see it, to be sure of what it says. But if it’s a decision the attorney has been given the power to make, it’s theirs to make – though they should consult doctors and care staff to make sure they know all the facts. If someone is worried that an LPA attorney is not acting in the person’s best interests,  this should be reported immediately to the Office of the Public Guardian: for how to do this, and for more about LPAs, see here.



If someone has a deprivation of liberty safeguards (DoLS) authorisation to live in our care home, we should never let them out of the door and certainly not let them go to stay overnight with relatives or friends.


A DoLS authorisation gives a care provider the right to deprive someone of their liberty, but it does not compel them to do so any more than is absolutely necessary.

In fact, since the DoLS are part of the Mental Capacity Act, providers must always be looking for ways to lessen restrictions, if it can be done safely. Not only is it possible that someone may regain their capacity to make their own decisions about how and where to live, in which case any authorisation cannot remain in force, but – more commonly – an individual with a DoLS authorisation may be perfectly safe to go out on a country walk with a staff member or relative, or even to stay away with family or friends, perhaps for a birthday. Decide each situation on its own merits. For more about DoLS, see here.


Rachel Griffiths
Rachel Griffiths

Mental Capacity and Human Rights Specialist


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