What Age is Capacity Assessment For?

Oct 25, 2025 3 min read •

senior care Healthy Aging Legal Guidance

It's a common misconception that a capacity assessment is only for a certain age group, such as the very elderly. In fact, a capacity assessment can be initiated for any adult aged 16 or 18 and older, depending on jurisdiction, whenever their ability to make a specific decision is in question due to an impairment of the mind or brain.

Quick Summary

A capacity assessment is not based on a person's age but is initiated when an adult's ability to make a specific decision is called into question due to a cognitive impairment. The process focuses on a person's functional ability at a specific time, not a universal lack of competence, ensuring their autonomy is respected.

Key Points

Functional Ability, Not Age: A capacity assessment is not tied to a specific age but is based on a person's functional ability to make a specific decision at a specific time [1, 4].
Presumed Capacity for Adults: In most jurisdictions, all adults (16 or 18+) are legally presumed to have capacity unless proven otherwise, placing the burden of proof on the assessor [1, 2, 5].
Decision-Specific Nature: Capacity is not an all-or-nothing state; a person may have the capacity to make some decisions but not others, requiring an assessment for each specific issue [4, 5].
Impairment Requirement: An assessment requires evidence of an impairment or disturbance in the functioning of the mind or brain, which could be temporary or permanent [3, 5, 6].
Clinical vs. Legal: Clinical capacity is a medical determination made by a clinician for a specific decision, whereas legal competence is a court-ordered declaration of a global legal status [2, 5].

Understanding the Core Principle: It's Not About Age

A capacity assessment is not triggered by a person’s age. It's prompted when there's a reasonable belief that an adult, typically 16 or 18 years and older depending on the jurisdiction, may have a cognitive impairment affecting their ability to make a particular decision [1, 2, 4]. Legal frameworks, like the UK's Mental Capacity Act 2005 or similar US principles, presume a person has capacity unless proven otherwise [1, 5]. Simply being older, having a dementia diagnosis, or a physical illness doesn't automatically require an assessment. The process is decision-specific; someone might have capacity for some decisions but not others [4, 5]. Thus, capacity assessment timing is about a moment when concerns arise, not a birthday [4].

The Legal Age Threshold and Presumption

While not age-dependent for initiation, there's a legal age for presumed capacity, similar to the age of legal majority [2, 5]. In the UK, this is 16; in the US, generally 18, with some medical consent exceptions [2]. This presumption means the burden is on the person raising concerns to justify an assessment, protecting autonomy [5].

Triggers for a Capacity Assessment

Capacity assessment is a clinical and legal tool used when specific circumstances question decision-making ability [4]. Common triggers include:

Significant Health Changes: Conditions like stroke, brain injury, or dementia can raise concerns about understanding medical options [4].
Questionable Financial Decisions: Poor decisions due to impairment, like falling for scams, may necessitate a financial capacity assessment [4].
Resistance to Necessary Care: Refusing essential treatment may prompt questioning if the person understands the consequences [4].
Planning for the Future: Concerns about understanding documents like a Lasting Power of Attorney can trigger an assessment [4].
Safety Concerns: Impaired judgment leading to safety risks can lead to assessment regarding living arrangements [4].

The Two-Stage Test for Capacity

Many jurisdictions use a two-stage test for determining lack of capacity [3, 5, 6]:

Diagnostic Stage: Confirming an impairment or disturbance in the mind or brain, which can be temporary or permanent [3, 5, 6].
Functional Stage: If an impairment exists, assessing if it prevents the person from making the specific decision [3, 5, 6].

The Four Abilities Assessed

Capacity for a decision requires demonstrating four abilities [3, 5, 6]:

Understanding Information: Comprehending relevant information, including risks and benefits [3, 5, 6].
Retaining Information: Holding information long enough to use it [3, 5, 6].
Weighing and Using Information: Evaluating options with a logical process [3, 5, 6].
Communicating the Decision: Expressing the decision clearly through any means [3, 5, 6].

Comparison: Clinical Capacity vs. Legal Competence

Clinical capacity (assessed by medical professionals) and legal competence (determined by a court) are distinct [2, 5]. Incapacity finding doesn't automatically mean legal incompetence [5].


Feature	Clinical Capacity	Legal Competence
Assessor	Treating clinician [2]	Judge [2]
Scope	Decision-specific and functional [5]	Global legal status [5]
Nature	Clinical judgment, can fluctuate [5]	Legal determination, court change only [5]
Purpose	Guides care; protects rights [5]	Transfers authority [5]
Trigger	Concern about specific decision [4]	Legal proceedings [5]

Best Practices and Conclusion

For families, respecting dignity and autonomy is vital [5]. Key principles include assuming capacity, supporting decision-making, and respecting unwise choices [5]. The least restrictive option is always the goal [5]. If concerned, have open conversations and seek professional advice [4]. Documentation is important [4]. Capacity assessment is a safeguard, protecting self-determination for adults of any age and only restricting autonomy when necessary to prevent harm [4, 5].

For more information on legal and ethical considerations, the American Bar Association offers resources on capacity assessments.

Frequently Asked Questions

A capacity assessment becomes relevant for adults, typically starting at age 16 or 18, depending on the jurisdiction. It is not an age-based test but is initiated when there is concern that an adult's ability to make specific decisions is impaired [1, 2, 4].

Yes, a person with dementia can still have capacity. Capacity is decision-specific, meaning an individual with dementia may be able to make some decisions but not others. The assessment is functional and must determine if their impairment prevents them from making the specific decision in question [4, 5].

No, absolutely not. Reaching an advanced age is not a trigger for a capacity assessment. The assessment is only initiated when there is specific evidence that a person's cognitive impairment is affecting their ability to make a particular decision [4, 5].

A capacity assessment can be requested by a medical professional, family member, or social worker who has a reasonable belief that an adult's decision-making ability is compromised [4]. In formal legal proceedings, it is typically requested by a party to the case [5].

Clinical capacity is a medical and functional determination made by a clinician regarding a specific decision [2, 5]. Legal competence is a broader, global legal status determined by a judge in court [2, 5]. A finding of incapacity by a clinician does not automatically mean legal incompetence [5].

The four key abilities are: understanding relevant information, retaining that information, weighing the information to make a decision, and communicating the decision. A person must demonstrate all four abilities for the specific decision at hand to be deemed to have capacity [3, 5, 6].

You can support a loved one by providing information in a clear and simple way, giving them plenty of time, involving them in discussions, and ensuring they are in a comfortable environment. Always assume they have capacity until proven otherwise and follow the principle of providing the least restrictive support [5].

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.