Mental capacity assessments – Who can carry them out and when

Mental capacity assessments are a vital part of determining whether an individual can make decisions for themselves, particularly regarding their health, welfare, property, and finances. As Capacity and Care specialists, we support clients through every stage of this complex process.

Understanding how and when to carry out mental capacity assessments is key to ensuring legal compliance and safeguarding the individual’s rights. These assessments are central to the framework of the Mental Capacity Act 2005, which applies in England and Wales.

What is a mental capacity assessment?

A mental capacity assessment evaluates whether someone is able to make a particular decision at a particular time. It is not about making a general judgment on someone’s intelligence or mental health, but rather on their ability to understand, retain, use, and weigh relevant information and communicate their decision effectively.

• Understand: Can the person comprehend the information relevant to the decision?
• Retain: Are they able to remember that information long enough to make a decision?
• Use or weigh: Can they weigh that information to make a decision?
• Communicate: Are they able to convey their decision by any means (speech, visual aids, sign language, etc.)?

When should mental capacity be assessed?

A capacity assessment should be carried out when:

1. There is reason to believe the individual’s capacity is in question for a specific decision.
2. The person is making decisions that appear irrational or harmful to themselves or others.
3. Medical, legal, or financial professionals are concerned about the person’s ability to understand the implications of a decision.

According to the Mental Capacity Act 2005, it must be assumed that a person has capacity unless it is established that they lack it. Any capacity assessment should relate specifically to the decision in question and not be overly broad.

Who can carry out a mental capacity assessment?

Various professionals can conduct mental capacity assessments, depending on the context:

• Doctors: Especially in healthcare settings, when decisions about treatment or discharge are involved.
• Social workers: Typically assess capacity in the context of care planning or safeguarding concerns.
• Solicitors or legal professionals: May assess capacity for legal matters such as making a Will or granting Power of Attorney.
• Independent Mental Capacity Advocates (IMCAs): Instructed when a person has no one to support them and serious decisions are required.

In complex or contested cases, it may be appropriate to involve a psychiatrist or psychologist for a more in-depth assessment.

The legal framework behind mental capacity assessments

The Mental Capacity Act 2005 sets out a two-stage test for mental capacity:

1. Is there an impairment of, or disturbance in, the functioning of the mind or brain?
2. If so, is the impairment or disturbance sufficient to make the person unable to make the particular decision?

The assessment must be decision-specific and time-specific. Just because someone lacks capacity for one decision does not mean they lack it for all decisions.

Common scenarios that require capacity assessments

Examples of when assessments are often needed include:

• Creating or revoking a Lasting Power of Attorney (LPA).
• Making a Will (testamentary capacity).
• Refusing or consenting to medical treatment.
• Entering into contracts or financial arrangements.

Case scenario

Mrs. L, an 82-year-old with early-stage dementia, wished to make a Lasting Power of Attorney for her son to manage her property and finances.  Her solicitor who acted as the Certificate Provider expected she might not fully understand the implications of the document and was struggling to remember what finances she had, so a capacity assessment was arranged.  The solicitor assessed her capacity using the five principles of the Mental Capacity Act 2005.  The solicitor found her to not have mental capacity and therefore the family arranged a deputyship order for the son to manage Mrs. L’s property and finances.

Expert insights on mental capacity assessments

Legal and medical professionals stress the importance of:

• Recording the assessment process clearly and thoroughly.
• Using plain, jargon-free language with the individual.
• Ensuring assessments are proportionate to the decision.
• Involving relevant family members or advocates when appropriate.

Our specialist Court of Protection & Vulnerable Persons team are dedicated to supporting and protecting the interests of those who no longer have the mental capacity to make their own decisions. Whether this is through illness, disability, or injury, we work with a range of vulnerable clients and their families to overcome the often complex legal issues that arise in these circumstances. We can help you at every step with friendly, empathetic, and expert legal support.

Contact us for more information.

Benefits and challenges

Benefits:

• Protects vulnerable individuals by ensuring professionals are involved when capacity is in question.
• Promotes autonomy and decision-making rights.
• Prevents exploitation or undue influence.

Challenges:

• Complex or borderline cases can be difficult to assess.
• Disagreements between family members and professionals.
• Time-sensitive decisions may create pressure.

Mental capacity assessments – FAQs

What is a mental capacity assessment?

A mental capacity assessment determines whether someone can make a specific decision at a given time. It involves checking if the person can understand, retain, weigh relevant information, and communicate a decision.

Who is legally allowed to carry out a mental capacity assessment?

Doctors, social workers, legal professionals, and Independent Mental Capacity Advocates (IMCAs) can all carry out assessments, depending on the nature of the decision being made.

When should a capacity assessment be carried out?

It should be carried out whenever there are questions about a person’s ability to make a particular decision, especially when medical, welfare, legal, or financial issues are involved.

What happens if someone is found to lack capacity?

If a person lacks capacity, decisions must be made in their best interests. This may involve family members, carers, or the Court of Protection, depending on the circumstances.

Definition of “mental capacity assessment”

A process used to determine whether an individual can make a specific decision at a specific time, guided by principles in the Mental Capacity Act 2005.

The five principles of the Mental Capacity Act 2005:

1. A person must be presumed to have capacity unless proven otherwise.
2. All practicable steps must be taken to help a person with the mental capacity assessment.
3. An unwise decision does not mean a person lacks capacity.
4. Any decision or action taken on behalf of a person lacking capacity must be in their best interests.
5. Any decision or action taken on behalf of a person lacking capacity should aim to be the less restrictive option available.

This article was produced on the 3rd December 2025 for information purposes only and should not be construed or relied upon as specific legal advice.