How is Mental Capacity Assessed?

What Is Mental Capacity?

Mental capacity refers to a person’s ability to make a specific decision at the time it needs to be made i.e., it is both decision-specific and time-specific. This means that a person may have the capacity to make some decisions but not others, and capacity can fluctuate over time.

“The purpose of every capacity assessment is to take away ambiguity and replace it with unquestionable clarity, which is why only the most solid assessments and reports will do. Halcyon Doctors stand out in providing this.”

Decisions commonly requiring professional assessment include:

• Managing property and financial affairs
• Making a will
• Making a gift
• Making a lasting power of attorney
• Choosing where to live or what care to receive
• Litigate or standing trial

The starting point is always the presumption of capacity – every adult has the right to make their own decisions and must be assumed to have capacity unless proven otherwise. Assessments are only carried out when there is reasonable cause to overturn this presumption.

The Legal Framework for Capacity Assessments

The Mental Capacity Act 2005

In England and Wales, the Mental Capacity Act 2005 (MCA) provides the legal framework for assessing capacity. It sets out the core principles that guide every assessment and decision made under the Act.

There are five key principles that underpin the MCA:

1. Presumption of capacity – every adult has the right to make their own decisions unless proven otherwise.
2. The right to make unwise decisions – people are free to make choices others may disagree with.
3. Support to make decisions – all practicable help should be given to enable a person to decide for themselves.
4. Best interests – any decision made on behalf of someone lacking capacity must be in their best interests.
5. Least restrictive option – decisions should interfere as little as possible with a person’s rights and freedom of action.

These principles ensure that capacity assessments are both fair and respectful of individual autonomy, balancing protection with empowerment.

The MCA provides a clear two-stage test for capacity:

1. The Functional Stage: Is the person able to make the decision?
2. The Diagnostic Stage: If they are not, is it because of an impairment or disturbance in the functioning of the mind or brain (causal nexus) ? This could be due to conditions such as dementia, a learning disability, a brain injury, or a mental health condition.

The Four Tests of Capacity

A person is deemed unable to make a decision if they cannot fulfil one or more of the following functions:

• Understand the information relevant to the decision.
• Retain that information long enough to make the decision.
• Weigh up the information as part of the decision-making process.
• Communicate their decision in any form (e.g., verbally, in writing, or through gestures).

The Capacity Assessment Process

A capacity assessment is not a general test of intelligence or memory. It is a structured process focused on whether an individual can make a specific decision at a specific time.

Assessments are usually carried out by qualified professionals, such as doctors, nurses, solicitors, or social workers. In more complex cases, or where legal robustness is essential, assessments are often conducted by medical specialists such as Consultant Psychiatrists.

Key factors considered include:

• Cognitive function (memory, attention, reasoning)
• Physical and mental health
• The complexity of the decision
• Any support or adjustments that can maximise capacity (e.g., using clear language, visual aids, or assessing at the best time of day)

What Happens During a Mental Capacity Assessment?

A thorough assessment typically involves:

• Clinical assessment including:
  •  A personal and family history
  • Medical history including prescribed medication
• Mental state examination: Exploring mood, beliefs, and thought processes.
• Cognitive testing: Using standardised tools such as the MOCA or ACE-III to measure memory, attention, and executive function.
• Collateral history: Gathering information from carers, relatives, or professionals (with consent) to build a complete picture of the person’s abilities over time. In cases of family conflict, the assessor must carefully navigate this to avoid bias.

What Makes a High-Quality Assessment?

The Importance of Clinical Insight

Whilst identifying a general cognitive impairment is the first step, it is often insufficient on its own. This is where a nuanced clinical assessment becomes invaluable.

Different diagnoses impact capacity in different ways. For instance, a person with Alzheimer’s dementia may struggle to retain information, while someone with frontotemporal dementia may retain facts but have difficulty weighing up risks and benefits due to impaired judgment.

Establishing a clear link between symptoms and the decision-making process is the cornerstone of a robust assessment. This is why assessments are significantly strengthened when conducted by, or in consultation with, clinicians such as Consultant Psychiatrists.

Indicators of a Robust Assessment

What Should a Mental Capacity Report Include?

A well-structured mental capacity report should be:

• Evidence-based – rooted in clinical and factual findings.
• Decision-specific – linked clearly to the matter in question.
• Comprehensive – covering all four tests of capacity.
• Legally robust – suitable for use in court or formal proceedings.

Reports are often required for:

• Lasting Power of Attorney (LPA) certification.
• Court of Protection matters (e.g., COP3 forms).
• Retrospective capacity assessments relating to past decisions, wills, or financial transactions.

Retrospective Capacity Assessments

These assessments consider whether someone had capacity at a particular point in the past – often in relation to a will, property transfer, or legal agreement. They require careful analysis of medical records, contemporaneous notes, and sometimes testimony from those involved. Because they can affect the outcome of legal disputes, they must be approached with exceptional care and precision.

Ensuring Fair and Robust Assessments

Assessing mental capacity is always decision-specific and time-specific. A person may lack the capacity to manage complex finances but retain the capacity to decide what to eat or who to have as a visitor. Capacity can fluctuate over time. A thorough, principled, and empathetic approach ensures that a person’s rights remain at the centre of the process.

At the same time, capacity assessments can carry life-changing consequences for individuals and their families. That’s why choosing the right professional matters. If you are unsure about an upcoming assessment, need advice, or wish to contact an expert, Halcyon Doctors can help. Our consultants provide clear, evidence-based assessments across England and Wales, trusted by legal professionals and families alike.

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