Capacity assessment (Assessment of mental capacity)
An assessment of whether a person can make a particular decision for themselves at a particular time, carried out under the law that applies where you live (the Mental Capacity Act 2005 in England and Wales) and designed to support the person to decide wherever possible.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- Capacity is decision-specific and time-specific: it is about one decision at one time, not whether a person is 'capable' in general.
- The law assumes capacity and protects the right to make unwise decisions — an assessment is not a way to override someone you disagree with.
- The person must be given all practical support to make the decision themselves before anyone concludes they cannot.
- Only if someone genuinely cannot decide can others act for them, and then only in their best interests and as little restriction as possible.
- The exact law depends on where you are in the UK: the Mental Capacity Act 2005 in England and Wales, the Adults with Incapacity (Scotland) Act 2000 in Scotland, and the Mental Capacity Act (Northern Ireland) 2016 — only partly in force — in Northern Ireland. The everyday principles are similar, but the legal detail differs.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Protects a person's right to make their own decisions wherever possible
A capacity assessment is not appropriate as a way to override a decision simply because others disagree with it — unwise decisions are allowed.
The person is given information and supported to make the decision, then explores it in conversation with the assessor. Breaks can be taken if needed.
A clear, plain-language record of the decision assessed, the support given and the reasons for the conclusion.
The person is given information and supported to make the decision, then explores it in conversation with the...
An opinion is usually reached for that specific decision, and the reasons are recorded. The person is told the...
Their decision stands and should be respected and acted on, even if others disagree with it.
A best-interests process begins, involving the person, family or attorneys, and the people providing care...
What is a capacity assessment?
A capacity assessment looks at whether a person is able to make a specific decision for themselves at the time it needs to be made. In England and Wales this is governed by the Mental Capacity Act 2005.
The law is not the same across the whole of the UK. In England and Wales the Mental Capacity Act 2005 and its Code of Practice apply. In Scotland the relevant law is different — the Adults with Incapacity (Scotland) Act 2000 — which has its own principles and its own way of certifying treatment for someone who cannot consent (often called a 'section 47 certificate'). In Northern Ireland there is the Mental Capacity Act (Northern Ireland) 2016, but only part of it has been brought into force so far, so exactly which rules apply can depend on the particular decision and setting. The everyday principles described below — supporting the person to decide, focusing on one decision at a time, and only stepping in to decide for them if they genuinely cannot decide for themselves — are broadly similar wherever you live, but the legal detail and paperwork differ (for example, Scotland's law talks about acting for the person's 'benefit' rather than their 'best interests'), so it is worth checking the framework for your nation.
It is important to understand what capacity means. The law starts by assuming every adult can make their own decisions. Capacity is about a particular decision, not the person as a whole — someone may be able to decide some things but not others, and capacity can change over time. The person must be given all reasonable help to decide before anyone concludes they cannot.
The law also protects the right to make what others see as an unwise or eccentric decision. Making a choice that family or doctors disagree with does not, by itself, mean someone lacks capacity. A capacity assessment is not a way to overrule a decision simply because others do not like it.
Only if a person genuinely cannot make a particular decision — even with support — can a decision be made for them, and then it must be made in their best interests and in the least restrictive way. The aim of an assessment is always to support the person to decide for themselves wherever that is possible.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Having capacity versus lacking capacity for a decision
| Has capacity | Lacks capacity (for this decision) |
|---|---|
| The person decides — even if others disagree | A best-interests decision is made for them |
| An unwise choice is allowed | Their past and present wishes still guide things |
| No best-interests process is needed | The least restrictive option is chosen |
| Support may still be offered | Capacity is re-checked as it can return |
Lacking capacity is never assumed from a diagnosis, age or appearance. It must be shown for the specific decision, and it can change.
Preparing for your test
- Be clear about the exact decision in question — capacity is assessed one decision at a time, not in general.
- Gather relevant background: medical letters, a list of medicines, and any history of memory, mental health or communication difficulties.
- Choose a good time of day and a calm setting, as tiredness, pain, infection or anxiety can affect someone's ability to decide.
- Make sure glasses, hearing aids and any communication aids are available, and arrange an interpreter if needed.
- Note who the person trusts and would like with them — though the person's own views, in private if needed, must be heard.
- Check whether the person has already made a Lasting Power of Attorney or an advance decision, as these may already cover the situation.
- Remember the starting point is that the person can decide, and the assessor's job is to support that wherever possible.
What happens
The assessor — often a doctor, nurse, social worker or other suitably experienced professional — first makes sure the person has all the information they need to make the decision, given in a way they can understand.
They then have a conversation, not a quiz. They explore whether the person can understand the relevant information, hold onto it long enough to use it, weigh up the pros and cons, and communicate a decision in any way — speech, writing, gestures or aids.
The assessor takes account of anything that might be temporarily affecting the person, such as illness, pain, medication, infection or the time of day, and may arrange to return at a better time.
A conclusion is reached for that specific decision, with the reasons recorded. If the person is found able to decide, their decision stands — even if others would have chosen differently. If they are found unable to decide even with support, a best-interests process follows, involving the person and the people close to them.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- A capacity assessment is not appropriate as a way to override a decision simply because others disagree with it — unwise decisions are allowed.
- It should not be carried out when a reversible cause such as infection, severe pain or acute confusion is untreated; treat that first and re-assess.
- It is not a general label for a person — it must be tied to a specific decision at a specific time.
- If the person is acutely unwell, their urgent medical needs come first, not a formal capacity judgement.
Delay or rearrange if…
- The person has acute illness, delirium, infection, severe pain or is heavily sedated.
- It is a poor time of day, or the person is too tired or distressed to take part.
- Reasonable steps to support the decision — information, aids, interpreter — have not yet been tried.
- Key information about the decision or the person is missing.
Alternatives to discuss
- Supported decision-making, giving more help so the person can decide for themselves.
- Treating a reversible cause and re-assessing when the person is at their best.
- Relying on an existing valid Lasting Power of Attorney or advance decision if one already covers the situation.
- A best-interests meeting only if the person genuinely cannot decide even with support.
- Referral to a court (the Court of Protection in England and Wales) for serious or disputed decisions.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Protects a person's right to make their own decisions wherever possible
- Makes sure people get real help to decide, not just a yes-or-no judgement
- Gives a clear, recorded basis for decisions about treatment, care or finances
- Helps avoid both extremes — neither ignoring someone's wishes nor wrongly taking control
- Ensures that, if a decision must be made for someone, it is in their best interests and as unrestrictive as possible
Risks & complications
- The conversation can feel personal, stressful or upsetting
- Disagreement may arise between the person, family and professionals about the outcome
- The result may not be what the person or family hoped for
- A poorly conducted assessment may confuse capacity with simply making a choice others dislike
- A snapshot on a bad day may underestimate what the person can actually do
- The findings may have significant consequences for treatment, care or living arrangements
- A serious dispute may need referral to a court (the Court of Protection in England and Wales)
- A safeguarding concern may come to light that has to be acted on
The biggest risk in a capacity assessment is getting it wrong in either direction — wrongly deciding someone cannot make a decision when they can, or missing that they genuinely cannot and need protection. Capacity must never be judged from a diagnosis, age or an 'unwise' choice alone. Ask how the person was supported to decide, what specific decision was assessed, and whether the assessment can be repeated at a better time. If a person is found to lack capacity, ask how their own past and present wishes are being respected.
Published figures to discuss
A capacity assessment is a judgement made under a legal framework, not a procedure with complication rates. The real uncertainty is the quality and timing of the assessment — whether the person was properly supported, whether a reversible cause was missed, and whether the right specific decision was assessed. Quoting numerical rates would not be meaningful or honest here.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Capacity being wrongly treated as global rather than decision-specific | Common medicolegal pitfall | A person may lack capacity for one complex decision but retain capacity for simpler choices; each decision needs its own assessment. | Guide sourcesClinical context |
| Delirium or acute illness causing temporary loss of capacity | Common in older hospital patients | Capacity can improve when infection, dehydration, pain, constipation, medicines or sleep disruption are treated. | GOV.UK — Mental Capacity Act Code of Practicegov.ukSource-linked context |
| Undue influence or coercion being missed | Uncommon but high impact | Private discussion, safeguarding awareness and checking the person's own values are essential. | Guide sourcesClinical context |
| Best-interests decision made without relevant people or preferences | A recognised source of poor decisions and complaints | Good assessment records the person's past wishes, family input where appropriate, least-restrictive options and why the decision cannot wait. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery from a capacity assessment. "Afterwards" is about what the conclusion means: whose decision it now is, what is recorded, and what happens next.
- Feeling emotionally tired or unsettled after a personal conversation
- Needing time for the person and family to take in the outcome
- Recognising that the result may change if it is re-assessed when the person is better
- Understanding that one decision being affected does not mean every decision is
Aftercare
- Make sure the conclusion and reasons are recorded clearly and shared appropriately.
- If the person has capacity, respect and act on their decision, even if others disagree.
- If a best-interests decision is needed, involve the person and those close to them, and keep it to the least restrictive option.
- Treat anything that may be temporarily affecting the person — such as infection, pain or low mood — and re-assess afterwards.
- Check whether an existing Lasting Power of Attorney or advance decision already applies.
- Know how to ask for a second opinion or formal review if there is disagreement.
- Keep the person informed and involved throughout, whatever the outcome.
- The specific decision clearly defined in advance
- Relevant medical and background information gathered
- A calm setting and a good time of day chosen
- Glasses, hearing aids, communication aids or interpreter arranged
- Any existing Lasting Power of Attorney or advance decision checked
- A trusted person available if the person wants them there
- A note of the person's own known wishes and values
⚠ Get urgent help if…
- A sudden change in the person's thinking or alertness, which may signal infection or acute illness needing urgent medical review
- New confusion alongside fever, pain, breathlessness or not passing urine
- Any sign the person is at immediate risk of harm to themselves or others
- A best-interests decision being made without involving the person or those close to them
- Capacity being judged purely from a diagnosis, age or an unwise choice
- Disagreement that cannot be resolved and may need a second opinion or referral to a court (the Court of Protection in England and Wales)
- Any thoughts of self-harm or that life is not worth living
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good capacity assessment results in a clear, well-reasoned conclusion about one specific decision, reached after the person has been genuinely supported to decide. If they have capacity, their decision is respected. If they do not, a best-interests process protects them while keeping their own wishes central.
An assessment cannot turn a difficult decision into an easy one, and it cannot predict the future. Capacity is not fixed — it can return, for example once an infection or low mood is treated — so a conclusion applies to that decision at that time and may need revisiting.
A capacity conclusion relates to a particular decision at a particular time. It is not a permanent label. Capacity can fluctuate during the day, improve when a treatable cause is addressed, or change as a condition progresses. For ongoing or repeated decisions, capacity should be reconsidered each time rather than assumed from a previous assessment.
Related tests, treatments or support
A capacity assessment often sits alongside a wider review — for example a memory assessment, a comprehensive geriatric assessment, treatment of delirium or depression, or advance care planning. Where someone is found to lack capacity for important decisions, conversations about a Lasting Power of Attorney (for future decisions while capacity remains) or best-interests planning may follow.
Follow-up & long-term care
Follow-up depends on the decision and the outcome. The conclusion and reasons are recorded and shared appropriately. If a treatable cause may be affecting the person, it is addressed and capacity re-assessed. For best-interests decisions, the person and those close to them stay involved, and disagreements can be reviewed, escalating to a court (the Court of Protection in England and Wales) only if necessary.
- Reconsider capacity for each new or repeated decision rather than assuming it from before
- Treat and re-assess if a reversible cause such as infection, pain or low mood is found
- Keep records and any best-interests decisions under review as circumstances change
- Review whether a Lasting Power of Attorney would help with future decisions while capacity remains
Repeat, follow-on and what comes next
- Capacity can fluctuate, so a conclusion may need revisiting for the same or future decisions.
- An assessment done on a bad day may underestimate the person and should be repeated when they are better.
- Best-interests decisions are not fixed and should be reviewed as circumstances change.
- Disputes can be escalated to a court (the Court of Protection in England and Wales) if they cannot be resolved.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear, plain-language record of the decision assessed, the support given and the reasons for the conclusion.
- Respecting and acting on the person's decision if they are found to have capacity.
- Involving the person and those close to them in any best-interests decision, choosing the least restrictive option.
- Treating any reversible cause and arranging re-assessment where capacity may return.
- A clear route to a second opinion or formal review if there is disagreement.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The experience and profession of the assessor
- The complexity of the decision being assessed
- How much background information must be reviewed
- Whether more than one visit is needed
- Whether an interpreter or communication specialist is required
- The detail of the written report, especially for legal or financial purposes
- Any follow-up or re-assessment
- The assessor's fee and their relevant experience
- Which specific decision the assessment covers
- Whether a written report is included and what it will contain
- The cost if more than one visit is needed
- Any charge for an interpreter or communication support
- Whether re-assessment is included if capacity may change
- The cancellation policy
On the NHS? Capacity assessments are carried out routinely as part of NHS health and social care when a decision arises; private and medico-legal assessments are also available, for example for property and financial affairs.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Judging capacity from a diagnosis, age or appearance rather than the specific decision.
- Treating an unwise or eccentric choice as proof of lacking capacity.
- Failing to give real support before concluding the person cannot decide.
- Not telling the person the outcome or involving them in a best-interests decision.
- Assessing on a bad day, or while a treatable cause is untreated, and treating the result as final.
Marketing red flags
- Offering to provide a capacity report to a particular conclusion to suit one party.
- Suggesting a single assessment can permanently declare someone 'incapable'.
- Skipping support for the person's own decision-making to reach a quicker answer.
- Marketing assessments as a routine way to take control of an older person's affairs.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Exactly which decision is being assessed, and why now?
- How have you supported the person to make this decision themselves?
- Could anything temporary — illness, medication, the time of day — be affecting them, and should this be reviewed first?
- If the person has capacity, how will their decision be respected even if family disagree?
- If they lack capacity, how will their own past and present wishes guide a best-interests decision?
- How can we ask for a second opinion or review if we disagree?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Does a diagnosis of dementia mean someone lacks capacity?
Can a capacity assessment be used to overrule a decision I disagree with?
Who can carry out a capacity assessment?
What happens if someone is found to lack capacity?
Can capacity come back?
What if we cannot agree on the outcome?
Is the law on capacity the same everywhere in the UK?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: SCIE — Mental Capacity Act 2005 at a glance GOV.UK — Mental Capacity Act Code of Practice NHS — Mental Capacity Act Mental Capacity Act 2005 (legislation) British Geriatrics Society — Mental capacity resources Adults with Incapacity (Scotland) Act 2000 — section 47 certificate guidance Mental Capacity Act (Northern Ireland) 2016 — information GOV.UK — changes to the definition of deprivation of liberty (2 June 2026)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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