Reviewed and revised 6 November 2014
- Capacity is a functional term that refers to the mental or cognitive ability to understand the nature and effects of one’s acts
- Competence is a legal term that can be defined as being “duly qualified: having sufficient, capacity, ability or authority” — in practice it requires health professionals to perform a functional test of competence to examine the ability of the particular patient to consent to the specific treatment being offered
- Capacity and competence are often used interchangeably
PRESUMPTION OF COMPETENCE
- In Australia at common law and under some statutes, adults (people over 18) are presumed to be competent, although it is possible to rebut the presumption by showing that an adult lacks competence
- In some states the presumption of competence has been extended to people younger than 18
- The presumption is reversed for children — they are presumed to be incompetent unless they can prove otherwise
ELEMENTS REQUIRED TO DEMONSTRATE COMPETENCE
- Demonstrating competence involves 4 important elements, the ability to:
1. maintain and communicate a choice
2. understand the relevant information
3. appreciate the situation and its consequences
4. manipulate the information in a rational fashion
- Testing understanding is extremely difficult
- the law does not require any specific types of tests of competence
- Useful questions to ask:
1. What is your present physical condition?
2. What is the treatment being recommended for you?
3. What do you and the doctor think will happen to you if you decide to accept treatment?
4. What do you and your doctor think will happen to you if you do not accept the recommended treatment?
5. What are the alternatives available (including no treatment) and what are the possible consequences of accepting each?
PITFALLS AND CHALLENGES
- Cognitive impairment is widely under-recognised, up to 60% of people with mild-moderate cognitive impairment are undiagnosed
- Competence can vary over time
- A mental illness does not necessarily imply a lack of capacity to consent, if the above elements can still be satisfied
- Competence is specific and/or can vary with specific tasks — a patient may be competent to consent for a simple procedure but not a complex procedure
- The patient’s decision need not be one that others would regard as reasonable, but it must involve a process of reasoning
- improvements in the patient’s level of comfort may improve competence – giving them time to think, allowing the support of friends and relatives, treating any reversible symptoms, such as pain, that may be compromising their capacity, or putting them in a quiet room or somewhere with a non-threatening atmosphere
- comprehensive testing (e.g. neuropsychiatric testing) and extensive corroborative testing is advised if there is disagreement between health professionals, or between them and patients or guardians
- the more serious the decision that has to be made, the greater the care needed to ensure that competence can be presumed
- simple cognitive tests such as the Mini-Mental State Examination are flawed (e.g. culture-specific, does not adequately address individual cognitive domains)
- Children (see Consent and competence in children)
- the issue of obtaining consent from a person to assess their capacity when they potentially lack the capacity is a dilemma!
References and Links
- CCC — Consent
- CCC — Consent and competence in children
- CCC — Treatment Decisions when patients lack competence
Journal articles and textbooks
- Purser KJ, Rosenfeld T. Evaluation of legal capacity by doctors and lawyers: the need for collaborative assessment. Med J Aust. 2014 Oct 20;201(8):483-5. PubMed PMID: 25332040. [Free Full Text]
- Snow HA, Fleming BR. Consent, capacity and the right to say no. Med J Aust. 2014 Oct 20;201(8):486-8. PubMed PMID: 25332041. [Free Full Text]
- Stewart C, et al. The Australian Medico-Legal Handbook (1st edition), Elsevier,2007 [Google Books Preview]