Mental Capacity


Having mental capacity means that a person is able to make their own decisions.

If the person you care for lacks the mental capacity to make decisions about money, health and other matters, you may need to help them to make those decisions, or you may have to act or make decisions on their behalf. The Mental Capacity Act is a law that sets out what should happen in this situation.

Read about the Mental Capacity Act in detail.

What is Mental Capacity?

The legal definition says that someone who lacks mental capacity cannot do one or more of the following four things:

  • Understand the information given to them.

  • Retain that information long enough to be able to make a decision.

  • Weigh up the information available to make a decision.

  • Communicate their decision.

We all have problems making decisions from time to time, but the Mental Capacity Act is about more than that. It is specifically designed to cover situations where someone is unable to make a decision because their mind or brain is affected, for instance, by illness or disability, or by the effects of drugs or alcohol.

A lack of mental capacity could be due to:

  • a stroke or brain injury

  • a mental health condition

  • dementia

  • a learning disability

  • confusion, drowsiness or unconsciousness because of an illness or the treatment for it

  • substance misuse.

In all of these instances, the person may lack the capacity to make particular decisions at particular times. Capacity is decision-specific; it does not necessarily mean that they lack the capacity to make any decisions at all. A person with a learning disability may lack the capacity to make major decisions but this does not necessarily mean that they cannot decide what to eat, wear and do each day. A person with a mental health condition may be unable to make decisions when they are unwell, but able to make them when they are well, this is referred to as fluctuating capacity.

Who decides if someone has the capacity?

Anyone in a position where they might need to make a decision for someone who may lack capacity must decide whether that person is able to make the decision on their own. In many cases that decision will be your responsibility. There will be times when a professional will need to make a decision about the person’s capacity. The Mental Capacity Act says that before you, or anyone else, acts on behalf of someone else they must have a ‘reasonable belief’ that the person lacks the capacity to make the decision for themselves. Anyone – a health or care professional, another professional, a relative or a carer – might need to decide if a person has the capacity to make a particular decision.

How could I be involved in assessing capacity?

You may be involved in assessing capacity in two ways:

  1. A professional may consult you about the person’s capacity. For instance, the person you are caring for might need to have an operation. The doctor might be unsure if the person has the capacity to consent to this. Often family members and those close to a person can provide valuable information to help assess a person’s capacity and help explain things in a way the person can understand.

  2. You may need to assess the capacity of the person because you need to do something in order to care for them. You are not expected to be an expert in assessing capacity, but you have to have a ‘reasonable belief’ that they lack mental capacity. You will need to think about;

  • Do they have a general understanding of what decision needs to be made?

  • Do they have a general understanding of the consequences of this decision?

  • Can they weigh up this information and use it to make a decision?

  • Is there any way you could help them to make the decision for themselves?

  • Is there any way you can help them communicate their decision or their wishes and feelings?

You will need to think about this for ‘big’ decisions such as where to live, and for everyday decisions about what to eat or what to wear. Just because the person makes a different decision from the one you would make or a decision you consider to be unwise does not mean that they lack the capacity to make that decision.

What if the person I am caring for lacks capacity?

If a person does not have the capacity to make the decision for themselves, then others will have to act in their best interests. Some people plan ahead and may have written an advance decision where they specified what sort of treatment they would not want to receive. Or they may have stated what sort of care or treatment they are willing to receive. Or they may have appointed an attorney to make certain decisions on their behalf.

Sometimes the Court of Protection will appoint a person to make decisions on their behalf called a ‘deputy’. If there is no relevant attorney or deputy with the necessary authority to make the decision in question someone else will have to decide what should happen. Depending on the particular decision, this could be you, or a professional. Whoever makes the decision must make it in the person’s best interests and in accordance with the principles of the Act.

How do I provide day-to-day care for someone who lacks capacity?

When a decision is made for a person who is not able to make that decision, it must always be made in the person’s ‘best interests’. This makes sure that:

  • the person’s rights are respected

  • the decision is the best one for them.

A decision should never be made in the best interests of anyone other than the person themselves. For example, a decision should never be made to make things easier for a carer or professionals who are caring for the person.