Mental capacity and decision making

A learning disability, autism, dementia, brain injury or mental-health condition does not automatically mean a person cannot make decisions.

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Start by assuming capacity

The Mental Capacity Act starts from the position that a person can make their own decision unless it is established that they cannot make that specific decision at the time it needs to be made.

The five principles

Assume capacity. Do not start from “they cannot decide”.
Give support first. Take practical steps to help the person understand and communicate their decision.
Unwise is not the same as incapable. People are allowed to make choices other people disagree with.
Best interests. If the person lacks capacity for that decision, any decision made for them must be in their best interests.
Least restrictive. Choose the option that interferes least with the person's rights and freedom while still achieving the necessary purpose.

Capacity is about one decision at one time

A person might be able to decide what to eat, how to spend a small amount of money and who they want to see, but not understand a complicated property transaction. Capacity can also change over time.

The question is not “Does this person have capacity?” in a general sense. The question is “Can this person make this particular decision now, with appropriate support?”

What does the capacity test look at?

The Mental Capacity Act test asks whether there is an impairment or disturbance in the functioning of the mind or brain and, because of that, whether the person is unable to make the particular decision.

For the decision itself, the person needs to be able to understand the relevant information, retain it long enough to make the decision, use or weigh it as part of deciding, and communicate the decision by any means.

Support before assessment

Support might mean using plain English, pictures, communication aids, extra processing time, a familiar person, a quieter environment, trying at a better time of day, breaking the choice into smaller parts, or presenting information in the person's preferred communication style.

If the person lacks capacity

A best-interests decision should not simply become “what the professional wants” or “what the family wants”. The decision-maker must consider the person's past and present wishes, feelings, beliefs and values, involve the person as far as possible, consider relevant circumstances and consult appropriate people.

Parents do not automatically keep legal decision-making power when a child becomes an adult

Being someone's parent or carer is important, but it does not by itself give legal authority over all adult decisions. The correct route depends on the decision and whether the person has capacity.

LPA, deputyship and DWP appointeeship

Arrangement	What it is	Key point
Lasting Power of Attorney (LPA)	A legal document made by a person who has capacity to appoint attorney(s).	There are property/financial affairs and health/welfare LPAs. The authority depends on the type and terms of the LPA.
Court of Protection deputy	A person appointed by the Court of Protection when ongoing decisions are needed for someone who lacks capacity and there is no suitable existing authority.	Deputies must act within the court order and Mental Capacity Act rules.
DWP appointee	Someone authorised to manage a person's DWP benefit claims and payments where the claimant cannot manage their own affairs.	Appointeeship is about benefits. It does not automatically give authority over bank accounts, health decisions or wider property.

When might the Court of Protection be involved?

The Court of Protection can make decisions or appoint deputies where a person lacks capacity and legal authority is needed. Serious disputes about accommodation, care, property or welfare may also require legal advice or a court decision.

What to ask if someone says “they lack capacity”

Which exact decision are you assessing?
What information does the person need to understand?
What support was tried before deciding they could not make it?
Was communication adapted to the person's needs?
Is the difficulty temporary or likely to improve?
Where is the assessment recorded?
If they lack capacity, who is the legal decision-maker for this decision?
How were the person's own wishes and feelings included?
What less restrictive alternatives were considered?

Related Awareverse pages

Learning Disability information · Supported Living & Housing · Direct Payments · Transition to Adult Services

Official sources used for this page

Rules can change. These links are included so you can check the current official position.

Mental Capacity Act information on this page applies to England and Wales. Last reviewed: 21 September 2026.