Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
39 Essex Chambers, Mental Capacity Guidance Note: Carrying out and recording capacity assessments.
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Copyright © 2026 Nellie Supports Ltd. All rights reserved.
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Unwise Decisions Versus Lack of Capacity
The right to make unwise decisions is a pillar of the Mental Capacity Act 2005: an eccentric, risky or even alarming choice is not evidence of incapacity. The legal question is never whether the decision is wise but whether the person can understand, retain, use and weigh the relevant information and communicate a choice. The distinction matters most under pressure, when families and professionals most want to intervene, and it is exactly where careless assessments go wrong. This guide explains the boundary, the case law behind it and how a proper assessment protects both the person's autonomy and everyone else's peace of mind.
The right to make unwise decisions
Section 1 of the Mental Capacity Act 2005 states that a person is not to be treated as unable to make a decision merely because they make an unwise one. Capacitous adults can make choices that family or professionals find risky, eccentric or plainly wrong. Disagreeing with a decision is not a basis for finding that the person lacks capacity.
Why this principle exists
The principle protects autonomy. If unwise decisions could be treated as evidence of incapacity, anyone making an unconventional choice could be overridden. The law deliberately separates the quality of a decision from the ability to make it, so that the right to self-determination is not lost simply because others would choose differently.
Where the line actually lies
The line is between a decision that is unwise but made with capacity, and a decision a person cannot make because they cannot use or weigh the relevant information. A capacitous person can understand the risks and choose to accept them. A person who lacks capacity cannot bring those risks to bear on the decision at all.
The danger of the protection imperative
Professionals can be drawn into what the courts have called the protection imperative, where a wish to keep someone safe leads to a finding of incapacity that the evidence does not support. A series of unwise decisions may prompt an assessment, but the assessment must still test ability, not simply react to risk.
When repeated unwise decisions raise a question
A pattern of harmful or self-defeating decisions can be a legitimate trigger for assessment, particularly where it is out of character or coincides with a change in cognition. The point is that it triggers a proper assessment of the ability to use and weigh information, rather than itself proving that capacity is absent.
Distinguishing values from impairment
People make decisions based on their own values, beliefs and priorities, which may differ greatly from the assessor's. A decision rooted in long-held values is very different from one driven by a delusion, compulsion or an inability to take in the consequences. The assessor must separate a value-based choice from an impairment-driven one.
How assessors should approach it
A careful assessor records the decision, the relevant information including its consequences, and whether the person can understand, retain, use and weigh that information. If the person can do so and simply chooses differently, they have capacity. The reasoning, not the outcome, is what the assessment examines.
Documenting the distinction
A defensible assessment explains why a decision is unwise yet capacitous, or why an apparently unwise decision in fact reflects an inability to use or weigh information caused by an impairment. Recording this distinction clearly is essential, because it is exactly the point on which families and courts most often disagree.
Key takeaway
An unwise decision is not a lack of capacity. The law protects the right to make choices others would not make. Capacity turns on whether the person can understand and weigh the relevant information, not on whether their decision is sensible. Confusing the two is one of the most common errors in this field.
Frequently asked questions
Can someone be stopped from making a risky decision?
Not merely because the decision is risky. If the person has capacity for the decision, it is theirs to make. Intervention needs either a lawful basis such as safeguarding where coercion is involved, or a proper finding of incapacity followed by best interests decision-making.
Does an unusual lifestyle suggest a lack of capacity?
No. Lifestyle, values and eccentricity are protected by the Act. An assessor's job is to test decision-making ability against the relevant information, not to grade the person's choices against convention.
How do you tell an unwise decision from incapacity?
Look at the reasoning, not the outcome. A capacitous unwise decision shows a person who understood the options and consequences and chose according to their own values. Incapacity shows itself as an inability to grasp, retain, use or weigh the information, however well the conversation is supported.
Related mental capacity assessment pages
These internal links help readers move from this guide to the most relevant Nellie Supports service page, assessment option or legal framework page.
Unwise decision or capacity concern?
Nellie Supports provides independent, decision-specific mental capacity assessments across England and Wales through a permanent employed team of registered professionals, with a same working day response to every enquiry and every report peer reviewed before delivery. Call 0333 987 5118 or visit the mental capacity assessment service page.