4C: MCA – LEGAL TEST

  1. There is a single legal test in the MCA defining lack of capacity. The key provision for determining capacity is s 2(1) of the MCA:584
    For the purposes of this Act, a person lacks capacity in relation to a matter if at the material time he is unable to make a decision for himself in relation to the matter because of an impairment of, or a disturbance in the functioning of, the mind or brain.
  2. There are two limbs to the capacity test in s 2. These are:585
  1. Whether the person is “unable to make a decision for himself” (functional test – as defined
    in s 3); and

  2. Whether that inability is because of “an impairment of, or a disturbance of the functioning of, the mind or the brain” (diagnostic test – as set out in s 2).
  1. Section 3 defines what it means to be unable to make a decision in terms of the functional approach. In summary, the four elements of the functional test are the inability to: understand, retain, or use or weigh the relevant information as part of the decision-making process, or communicate their decision.586

  2. The MCA definition of capacity reinforces that capacity is time-specific (at the material time) and decision-specific (unable to make a decision). It applies for the purposes of the Act, which in English law includes questions of capacity in relation to medical treatment decisions.587 Common law definitions of capacity such as capacity to make a will are not affected.588 When cases on such matters outside the Act come before the courts, judges can adopt the definition of capacity contained in this section and s 3 if they think it is appropriate.589

  3. difficulty in applying a strictly decision- or act-specific approach to capacity, within the MCA, has arisen in cases involving vulnerable women with learning disabilities that have been concerned with whether the women had capacity to consent to cohabit or have sexual relations.590 In IM v Liverpool,591 LM was found to have capacity to consent to sex, where the man involved challenged the supervision of his contact with LM that was carried out by the local authority. The Court of Appeal followed an act-specific approach, based on whether the person understood at a general level the nature of sex, to which they were apparently consenting, in contrast to a person-specific approach, requiring a more contextual analysis of the circumstances of the particular person.592 This reasoning suggests that the test of capacity to consent to sex merely involves being able to understand the nature of the activity, rather than having the ability to use or weigh information about it. The extent to which the capacity test in the MCA deals with these hard cases, where the person’s ability for autonomous decision-making is impaired, has therefore been called in question.593

584 Mental Capacity Act 2005, s 2(1).

585 A Ruck-Keene, V Butler-Cole, N Allen and others, above n 201.

586 The functional test in s 3 of the MCA is discussed below. Both ss 2 and 3 of the MCA are set out in full in Appendix C.

587 In New Zealand, the HDC Code provides the basis of the law of consent in relation to healthcare procedures but there is no definition of “competence”, discussed below.

588 Banks v Goodfellow (1869-70) LR5 QB 549. The Code of Practice recognises the common law tests of capacity to make a will, gift, enter a contract, to litigate and to enter a marriage.

589 Local Authority X v MM and KM [2007] EWHC 2003 (FAM) at [80], Munby J.

590 The consequences of finding that a person lacks capacity to consent to sex means that nobody else can consent to sexual relations on their behalf: Mental Capacity Act 2005, s 27(1)(b).

591 IM v LM and Liverpool City Council [2014] EWCA Civ 37. Another case, PC and NC v City of York Council [2013] EWCA Civ 478, McFarlane LJ, is discussed below in respect of causation.

592 The person or situation-specific test was supported by Lady Hale in a criminal law case involving consent: “One does not consent to sex in general. One consents to this act of sex with this person at this time and in this place” Regina v Cooper (2009) UKHL 42 at [27].

593 J Herring and J Wall “Capacity to Consent to Sex” (2014) 0 Med L Rev 1.


MCA – the functional test
  1. As with the PPPR Act, the MCA therefore mainly adopts a functional approach to defining capacity. The key difference is that there is just one legal test to follow, set out as four logical steps. A person is unable to make a decision if they cannot:594
  1. understand the information relevant to the decision; or

  2. retain that information in their mind; or

  3. use or weigh that information as part of the decision-making process; or

  4. communicate their decision (whether by talking, using sign language or any other means).
  1. Section 3 is based on the common law test of capacity and there is no relevant distinction between them.595 In IM v LM, the Court of Appeal said that: 596
    Every single issue of capacity which falls to be determined under Part 1 of the Act must be evaluated by applying s 3(1) in full in considering each of the four elements of the decision- making process that are set out at (a) to (d) .... The extent to which, on the facts of any individual case, there is a need either for a sophisticated, or for a more straightforward, evaluation by either of these four elements will naturally vary from case to case and from topic to topic.
  2. The four elements in this test are considered below.
Understand the information
  1. It is not necessary that the person understands every element of what is being explained to them. The information relevant to a decision includes information about the reasonably foreseeable consequences of deciding one way or another, or failing to make a decision.597 An explanation of all relevant information must be given to the person using appropriate means of communication given their particular circumstances.

  2. Being able to understand the information is not the same as being able to pass an exam on it: the person should have a broad understanding of the basic information relevant to the decision. This concept is familiar to most lawyers, but may not be so familiar to doctors, who may set the bar too high.598

  3. In Heart of England NHS Foundation Trust v JB,599 JB suffered from severe schizophrenia and vascular disease. She was found to have capacity to refuse surgical treatment of her gangrenous leg against “shifting medical opinion”. Peter Jackson J held:
    [w]hat is required here is a broad, general understanding of the kind that is expected from the population at large. JB is not required to understand every last piece of information about her situation and her options: even her doctors would not make that claim. It must also be remembered that common strategies for dealing with unpalatable dilemmas – for example indecision, avoidance or vacillation – are not to be confused with incapacity. We should not ask more of people whose capacity is questioned than of those whose capacity is undoubted. [Emphasis added].

594 Mental Capacity Act 2005, s 3(1).

595 Local Authority X v MM and KM, above n 589 at [74], Munby J.

596 Above n 589 at [73].

597 Mental Capacity Act 2005, s 3(4).

598 PH and A Local Authority v Z Limited and R [2011] EWHC 1704 (FAM).

599 Above n 363 at [26]. Peter Jackson J “happily” distinguished the earlier and famous decision of Thorpe J in Re C (Adult: Refusal of Treatment) [1994] 1 WLR 290 at 295, the first reported case to give any clear guidance on questions of capacity in relation to medical treatment decisions, even though both cases involved people with delusional beliefs. In refusing amputation of his gangrenous leg, C preferred “to die with two feet than live with one”. Note also earlier discussion of capacity in, Re T, above n 555 and although the ultimate decision was unanimous, each of the four judges involved decided the question of the person’s capacity differently.


  1. Having the appropriate information, including the options available, to make the decision is vital to this process and is consistent with supporting people to make their own decisions, where possible. So it is said that a person must not start with a “blank canvas”.600
Retain the relevant information
  1. Retaining information for even a short time may be adequate in the context of some decisions. This will depend on what is necessary for the decision in question. The MCA specifies that “the fact that a person is able to retain the information relevant to a decision for a short period only does not prevent him from being regarded as able to make the decision”.601 4.49 Aids to recollection, such as notes, pictures, photographs and voice recordings, and parts of the mental state examination, may be helpful to assess how long the person can retain information. Can they remember three words? If they can’t, can they still give consistent answers when questioned about their decision?602 4.50 The ability to retain information is a discrete element of the MCA test and logically follows from the requirement to understand the information. There is no equivalent element in the PPPR Act tests. It is an important consideration, particularly with older adults or people with deteriorating memories.603
Use or weigh the Information
  1. Using and weighing information is the evaluative component of the MCA test. It requires the ability to reason about, or weigh up, information and to appreciate the consequences. This may be the most difficult element of assessing capacity as an unwise or irrational decision does not necessarily establish that a person has failed to use or weigh the information.

  2. The standard of “weighing up” or “using information” can be difficult if the person is weighing up the important information against their personal convictions, beliefs or values. It recognises that “different individuals may give different weight to different factors.”604 In Kings College NHS Foundation Trust v C and V,605 the COP had to consider whether C had the capacity to consent to life-saving renal dialysis that her doctors wished to give her following an attempted suicide. If the treatment were to have been administered the likelihood was that C would require dialysis for the rest of her life, and, if not, the inevitable outcome was that she would die. C’s refusal to consent was supported by her two daughters.606 In finding that C had the capacity to refuse treatment, MacDonald J held, contrary to the opinion of two experienced psychiatrists, that it had not been shown that C was unable to use and weigh the information relevant to the decision:607
    I am not satisfied that C lacks belief in her prognosis or a future that includes her recovery to the extent she cannot use that information to make a decision, or that C is unable to weigh her positive prognosis and the possibility of a future recovery in the decision making process.... ... it is also important in this case not to confuse a decision by C to give no weight to her prognosis having weighed it with an inability on her part to use or weigh that information.608

600 CC v KK, above n 362. This case is discussed in Chapter 2E: Supported Decision-making in practice and in case law.

601 Mental Capacity Act 2005, s 3(3).

602 Interview with Dr Frances Matthews, lawyer and GP (A Douglass, Dublin, June 2015).

603 Ruck Keene, Butler-Cole, Allen and others, above n 201 at [30].

604 LBL v RYJ and VJ [2010] EWHC 2665 (COP) Macur J cited with approval by Baker J in CC v KK at [65]: “There is, I perceive, a danger that professionals, including judges, may objectively conflate a capacity assessment with a best interests analysis and conclude that the person under review should attach greater weight to the physical security and comfort of a residential home and less importance to the emotional security and comfort that the person derives from being in their own home.”

605 Kings College NHS Foundation Trust v C [2015] EWCOP 80 at [8]. C was said to live an unconventional life where she placed a “significant premium on youth and beauty and on living a life that, in C’s words, ‘sparkles’”.

606 C made statements such as “They are doing their best to do everything they can for me and unfortunately that is not what I want” and “I know they need to save lives. But I have chosen a different route” at [87].

607 Kings College NHS Foundation Trust v C at [72]. At [35], MacDonald J suggested that a finding of incapacity requires the person asserting lack of capacity to demonstrate both an inability to use and weigh relevant information however this reasoning has been questioned as not an accurate interpretation of “use or weigh” and that s 3(1)(c) can be satisfied either by establishing that a person is unable to use or by establishing a person is unable to weigh. W Martin and F Freyenhagen of the Essex Autonomy Project “Use or Weigh? Or Use and Weigh? A Note on the Logic of MCA sec. 3(1)” (2015) 61 Ment Capac Law News 15.


  1. In concluding, MacDonald J noted that the decision was an unwise one:609
    The decision C has reached to refuse treatment dialysis can be characterised as an unwise one. That C considers that the prospect of growing old, the fear of living with fewer material possessions and the fear that she has lost, and will not regain, “her sparkle” outweighs a prognosis that signals continued life will alarm and possibly horrify many, although I am satisfied that the ongoing discomfort of treatment, the fear of chronic illness and the fear of lifelong treatment and lifelong disability are factors that also weigh heavily in the balance for C.
  2. There are also cases where the person concerned can understand information but where the effects of a mental disability prevent them from using that information in the decision-making process. For example, a person with anorexia nervosa may understand information about the consequences of not eating. But their compulsion not to eat might be too strong for them to ignore.610 Some people who have serious brain damage might make impulsive decisions regardlessofinformationtheyhavebeengivenortheirunderstandingofit.611 Undue influence and the overpowering will of a third party are also considered to have a role in this aspect of the capacity test, especially where a person with borderline capacity may be less able to resist pressure applied by others.612

608 Kings College NHS Foundation Trust v C at [86].

609 Kings College NHS Foundation Trust v C at [97].

610 In Re E (Medical Treatment Anorexia) [2012] EHHC 1639 (COP) Peter Jackson J at [49] “E’s obsessive fear of weight gain makes her incapable of weighing the advantages and disadvantages of eating in a meaningful way”. E could understand and retain the information relevant to her decision to refuse to eat, but she was unable to assign relative weight to the advantages, disadvantages and consequences associated with the decision to eat since, “the compulsion to prevent calories entering her system has become that card that trumps all others”.

611 Mental Capacity Act Code of Practice, above n 285 at 48.

612 Re T, above n 555 at 797, Lord Donaldson MR. The role of undue influence in the test of capacity was recognised by the Law Commission, above n 311 at 38.


  1. The nearest equivalent under the PPPR Act to the MCA’s criterion of “use or weigh” is its requirement “to foresee the consequences” of decisions. There is, however, a nuanced difference, as the MCA test focuses on the evidence of using or weighing information as part of the decision-making process rather than on predicting the outcome or the consequences of the decision itself. The difficulty with the PPPR Act’s concept of “foreseeing the consequences” concerns the extent to which anyone, with capacity or not, can be said to value or fully evaluate the consequences of a decision if that requires the risks and benefits of the decision to be internalised.613

  2. The concept of “appreciating” that nature of the decision is used in this context in the United States.614 In the recently passed Mental Capacity Bill in Northern Ireland, the notion of “appreciate the relevant information” has been added to the element of “use or weigh” in the MCA test.615 It arguably adds a subtle evaluative aspect to the MCA test by importing the notion that the ability to “use or weigh” requires an appreciation of the significance of the person’s situation and the probable consequences of the treatment options.
Communicate the decision
  1. The inability to communicate a decision is also recognised in the PPPR Act tests and is a stand-alone ground for incapacity, even if rarely employed. Examples where it would apply would include people who are unconscious or in a coma or those with a rare condition sometimes referred to as “locked-in syndrome”, who are conscious yet totally unable to communicate.616 Any form of communication suffices so long as the person can make themselves understood.617 The MCA and its Code of Practice also require that an explanation of the relevant matters be communicated to the person in a way that is appropriate to their circumstances (using simple language, visual aids or other means).618

  2. Where an individual cannot communicate a decision in any possible way, the MCA considers the individual unable to make a decision for themselves.619 People who have suffered a stroke, for example, are particularly disadvantaged, as their difficulty in communicating can mask capacity that would normally be revealed in conversation.620 There is increased focus on this element of capacity with the shift towards supported decision-making for people with disabilities under the CRPD.621

613 P Appelbaum and T Grisso “Assessing Patients’ capacities to consent to treatment” (1988) 319 N Eng L Med 1635. Some New Zealand decisions have referred to ‘appreciate’ instead of “foresee the consequences” test when applying the s 6 PPPR Act test: KR v MR, above n 556.

614 In relation to treatment decisions, the criteria expressed by Grisso and Appelbaum are: the ability to express a choice about treatment, to understand information relevant to the treatment decision, to appreciate the significance of the treatment information.

615 Mental Capacity Bill (Northern Ireland) 2015. The meaning of “unable to make a decision” in s 4(I) includes “(c) is not able to appreciate the relevance of that information and to use and weigh that information as part of the process of making the decision.” This element refers to “use and weigh” not “use or weigh” under s3(1)(c) of the MCA.

616 One of the few cases is the New Zealand case of Area Health Board v Attorney General [1993] I NZLR 235, where the person had Guillian Barre syndrome.

617 There are tools for communication with people with disabilities and recognition of the transactional nature of communication to support people in making decisions for themselves: Kim Rosen “Communication the keystone to supported decision-making” presentation to the Capacity Australia conference (November 2015, Sydney) see www.capacityaustralia.org.au/.

618 Mental Capacity Act 2005, s 3(2).

619 Mental Capacity Act 2005, s 3(1)(d).

620A Patchet, L Allan and L Erskine “Assessment of Fluctuating Decision-Making Capacity in Individuals With Communication Barriers: A Case Study” (2012) 19 Top Stroke Rehabil 75.

621 See Chapter 2E: Supported decision-making in Practice and in Case Law.


The “diagnostic threshold” and causation
  1. The main difference between the PPPR Act and the MCA’s tests for mental incapacity is that the MCA combines a functional test for decision-making ability with the so-called “diagnostic threshold”. The requirement of an “impairment of, or a disturbance in the functioning of, the mind or brain” is very broad and it is a misnomer to call it a diagnostic threshold.622 It may be permanent or temporary.623 It may include conditions associated with some forms of mental illness, dementia, significant learning disabilities, the long-term effects of brain damage, physical or medical conditions that cause confusion, drowsiness or loss of consciousness, concussion following a head injury, and the symptoms of alcohol or drug use. The essential characteristic is a disturbance in the functioning of the mind, so many mental illnesses could potentially include an inability to make decisions, although most of them do not.624

  2. The Essex Autonomy Project Report found that the diagnostic threshold was discriminatory of people with disabilities in terms of the CRPD and recommended that it be removed.625 However, it was argued that the MCA’s use of the functional test under s 3(1) as a trigger for substitute decision-making justifies a practice which would otherwise be discriminatory as it disproportionately impacts on persons with disabilities. Primarily, this is because the central aims of the MCA, as with the CRPD, are to empower people to make their own decisions wherever possible, and to protect people with impaired decision-making capacity who find themselves facing circumstances of risk.

  3. For a person to be found to lack capacity there must also be a causal connection between being unable to make a decision by reason of one or more of the functional elements set out in s 3(1) of the MCA (the functional test) because of an impairment of the mind or brain under s 2(1) (the diagnostic test). In PC and NC v City of York Council, 626 the issue of causation made all the difference in finding that PC, a woman with learning disabilities, had capacity to live with her seriously risky husband upon his release from prison. The Court of Appeal overturned the decision of the COP and held that while PC lacked capacity to understand the information and weigh it to make the decision to resume living with husband, PC’s difficulties in decision-making (although “significantly related to her mild learning disability”), were not shown to be a result of her mental impairment.627

  4. The s 2 diagnostic threshold was introduced as a device to limit the scope of MCA powers.628 An argument in favour of the diagnostic threshold in the MCA’s capacity test, concerning the functioning of the mind or brain, is that it serves a gate-keeping function to ensure that a person’s actions, or ability to make a decision, are not being scrutinised on the basis of unwise decisions alone. Ironically, the requirement of a diagnosis is now seen as non-compliant with the CRPD as it specifically discriminates on the ground of disability. The legal complexity associated with removing the diagnostic test is the risk that the change required for CRPD compliance will in turn result in a violation of art 5 of the European Convention on Human Rights.629 Unlike New Zealand, the United Kingdom finds itself in a difficult position of having to satisfy two international human rights requirements that pull in opposite directions. 630
Summary
  1. The functional test in the MCA offers a simple and straightforward legal test for defining capacity, in contrast to the multiple tests for capacity in the PPPR Act, and in contrast to the lack of any definition of competence at all in the HDC Code. The functional test in the MCA codifies the common law and is similar to the existing tests in the PPPR Act. The MCA test has already been accepted implicitly in New Zealand case law,631 and it has been adopted as part of a threshold test in a compulsory treatment Bill for addiction currently before the New Zealand Parliament.632

  2. It is not necessary for New Zealand to adopt the diagnostic threshold in the MCA as part of a legal test, as that element is unnecessary and can be considered discriminatory towards people with disabilities under the CRPD.

  3. In conjunction with a revised legal test, a Code of Practice with guidance for assessing capacity would be essential to avoid inconsistent and idiosyncratic interpretations of the legal test, and to ensure that the tenets of capacity – the presumption of capacity and the right to make unwise decisions – are applied.

622 It is not necessary for the impairment or disturbance to fit into one of the diagnoses in psychiatric diagnostic manuals such as ICD-X or DSM-V. (A Douglass, Interview with Dr Gareth Owen, psychiatrist, Kings College, London, 22 April 2015).

623 Mental Capacity Act 2005, s 2(2).

624 Hale, above n 194.

625 W Martin, S Michalowski, T Jutten and others Achieving CRPD Compliance: Is the Mental Capacity Act of England and Wates Compatible with the UN Convention on the Rights of Persons with Disabilities? If not, what next? (Essex Autonomy Project, University of Essex, 22 September 2014) at 16 -17.

626 PC v York City Council [2013] above n 591. PC had previously been found to have capacity to marry but the question before the court was whether she had capacity to cohabit with her husband.

627 Skowron, above n 205

628 Winterwerp v The Netherlands, above n 401 at 1. The reason for the diagnostic threshold was put in the definition of capacity was for compliance with art 5 of the ECHR and the requirement of “unsoundness of mind” requiring objective medical evidence.

629 Szerletics, above n 209 at 44.

630 The new Mental Capacity Bill in Northern Ireland has sought to qualify the “diagnostic” threshold to avoid discrimination on the ground of disability. See Chapter IA Setting the Context.

631 Chief Executive of the Department of Corrections v Canterbury District health Board and All Means All [2014] NZHC 1433 at [17]. In an application by the Department of Corrections as to the lawfulness of not providing medical treatment to a serving prisoner on a hunger strike, Mr All Means All, Pankhurst J accepted the expert psychiatrist’s evidence based on the MCA legal test that Mr All Means All had capacity to refuse medical treatment.

632 Substance Addiction (Compulsory Assessment and Treatment) Bill, 2015. The four criteria for the compulsory treatment for substance addiction in clause cl 7(a)-(d) include the “capacity to make informed decisions” under clause 9, and adopts the functional test for “inability to make a decision” in section 3(1) of the MCA.

  © Copyright 2017 Alison Douglass