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The Mental Capacity Act & Psychological Assessment: The Story So Far

Medico Legal

by Dr Richard Maddicks, Consultant Clinical Neuropsychologist, Psychology Chartered

‘The empowering ethos has not been delivered. The rights conferred by the Act have not been widely realised. The duties imposed by the Act are not widely followed’. House of Lords Select Committee (2014) on the Mental Capacity Act 2005 1

Like a captious mid-term report or Theresa May’s General Election post-mortem, the House of Lords Select Committee review of the implementation of the Mental Capacity Act (MCA) (2005) is unforgiving and offers up plenty to reflect on. The harsh appraisal is far removed from the legislation’s laudable intentions and prima facie commitment to protect the most vulnerable adults in society: ‘The primary purpose of the Mental Capacity Act (2005) is to promote and safeguard decision-making within a legal framework ……. by empowering people to make decisions for themselves wherever possible, and by protecting people who lack capacity by providing a flexible framework that places individuals at the heart of the decision-making process’ 2. The enduring paternalism of health services along with risk aversion in social care are specifically identified by the House of Lords Select Committee report as obstacles to embedding the principles of the Act in the day to day practice of professionals. In short, organisational cultures and broader political context are likely to militate against professionals changing how they think and practice about mental capacity.

However, ideological changes of this type are rarely meteoric and more typically incremental and anfractuous. The review may have failed to identify elusive changes in professional practice in health care. For example, the British Psychological Society Audit Tool for Mental Capacity Assessments suggests that ‘Applied psychologists have generally engaged well with the Mental Capacity Act and have viewed it as a useful means to empower and protect vulnerable groups’ 3. MCA guidance has possibly served to fortify the imperative of decision/issue specificity, provided a framework for best interest decision-making and elevated the importance of understanding the patient’s beliefs and values in the assessment process. The views and actions of clinical professionals and services must reference the broad ethos of the legislation i.e. that mental capacity is assumed and an ‘impairment of mind’ is a necessary but not sufficient condition of depriving someone of the right to make their own decisions, even if these decisions are imprudent or ‘unwise’. In respect of the latter, psychological assessment of the patient will often provide critical and nuanced evidence relating to the patient’s understanding of the issue(s), processing/retention of key information and broader reasoning abilities. Psychological assessment may include evidence from formal cognitive testing and scoring profiles including a range of psychometric measures, with reference to psychological theoretical models and concepts. Prudent interpretation and clear explanation of this evidence invariably becomes an important part of the task of weighing evidence in mental capacity assessments. If the House of Lords 2014 report serves as a hiatus in how we approach questions of mental capacity for vulnerable adults, what follows is a timely reflection on key aspects of psychological evidence.

Seduction by statistics: the perils of psychometric assessment

Facts are stubborn, but statistics are more pliable. (Mark Twain)

Whilst neuropsychological tests can be used for diagnostic purposes, their primary function in relation to capacity assessments is often in relation to step two of the MCA test i.e. is the impairment or disturbance of mind sufficient that the person lacks the capacity to make a particular decision? Psychologists will often emphasise the importance of test results in the capacity assessment process, reflecting their usefulness as objective evidence, augmenting or elaborating other clinical information and offering standardised, ‘norm’ based information relating to the patient’s cognitive skills and impairments. It is possibly for this reason that some psychologists fall into the trap of thinking that more testing will generate more certainty regarding capacity. Consequently, clinicians with a tendency to understate the limitations of psychometric scores in this context might do well to heed the warnings against the ‘construction of a capacimeter’ (Kapp & Mossman, 1996 4). It is argued that the most useful approach might be to focus on assessing the areas of cognitive functioning that appear to have ‘face validity’. For example, ‘failure’ on specific tests of deductive reasoning is likely to be directly relevant to the patient’s capacity to weigh up relevant information in the relation to the decision(s) in question (Newby & Ryan-Morgan, 2013 5). Studies of the cognitive predictors of financial abilities found that some cognitive functions are more heavily associated with finance-related functional status such as attention, executive functions, memory, working memory, verbal abstraction and arithmetic. Meanwhile, in the assessment of testamentary capacity there may be a bias towards memory (recognition as well as spontaneous recall), orientation, expressive and receptive language, and executive functions.

Despite these important observations, there are several points that psychologists and lawyers should always hold in mind when considering the contribution of psychometric evidence. Firstly, it is widely recognised that psychometric tests have limited predictive value in determining a client’s capacity. Secondly, it is normal for healthy children and adults to have some variability in their cognitive abilities and furthermore, to produce low scores, particularly when multiple tests are administered (Brooks et al, 2013 6). Thirdly, multiple test administration increases the risk of ‘false positives’ or type 1 errors, (i.e. incorrectly identifying erroneous impairments) necessitating extra caution in interpretation, an adjustment of the threshold of significance or the ‘Bonferroni correction’.

The psychology of decision-making

‘We think that we make our decisions because we have good reasons to make them. Even when it's the other way around. We believe in the reasons, because we've already made the decision’. (Daniel Kahneman)

As mental capacity is intrinsically linked to the process of decision-making, psychological theories surrounding decision-making in non-clinical populations assume high relevance. As highlighted by Professor Graham Powell 7there is a tendency for us to hold an idealised view of the rationality of the average person. Correspondingly, there is equally the likelihood of a psychologist jumping to the conclusion that an unwise decision reflects that part of the person that is irrational.

Many theories of reasoning and decision-making propose that we do not see the world directly but rather through a “lens” of ‘cues’ and selective information. Social judgement theory (Hovland & Sherif, 1980 8) highlights the tendency for individuals to begin from an “anchor” position in relation to a specific issue or question i.e. a preferred position reflecting their current attitudes and beliefs. Much decision-making would start from this point before any consideration of alternative views or new information. The further away the new information is from the person’s anchor position the increased likelihood there is of a ‘contrast effect’ whilst, conversely, ‘assimilation’ occurs when the new information is closer to the anchor. Thereafter, the involvement of the ‘ego’, or how much personal significance the issue has to the individual will play a key role in determining the individual’s flexibility to make changes to the anchor position in the process of reaching a decision. This particular theory has particularly relevance to our susceptibility to influence and persuasion. Meanwhile, alternatives, including the theory of reasoned action, emphasise ‘behavioural intention’ and the importance of the person’s attitude towards the expected outcome or result of the behaviour (rather than the decision itself). It also includes the person’s consideration of ‘subjective norms’ (including the influence other people might have on a person’s attitudes and behaviour).

The importance of these theories lies principally in dispelling the myth of dispassionate, mechanistic ideas of cognitive processing. The contribution of a number of complex, interactive cognitive and emotional variables to ‘socially normed’ judgements and decisions is often understated in capacity assessment. As social animals, we are continually striving to construct a view of ourselves that is consistent and reduces “dissonance” i.e. trying to minimise and modify conflictual or discrepant beliefs or views. As such, our views or beliefs are invariably ‘work in progress’ in a constant state of flux such that psychology assessments need to represent and describe this complexity in relation to the question in hand.

Executive Functioning

Those capacities that enable a person to engage successfully in independent, purposive, self-serving behavior (Muriel Lezak)

Theories of executive functioning have seen substantial growth and elaboration over the last 30 years, impacting significantly upon psychological assessment. This aspect of cognition often remains key to the assessment of mental capacity in view of its relevance to regulating thoughts, translating plans to action and learning from experience. However, the broad range of high level mental functions, including attentional control, organising, planning, multi-tasking and self-monitoring present unique challenges to clinicians both in terms of assessment and treatment. Traumatic brain injury might present specific challenges in this respect in terms of the vulnerability of frontal brain structures following many types of closed head injury. Consequently, clinical presentations of patients with significant emotional and behavioural changes in the context of relatively unaffected intellect are not uncommon.

Notably, the subtle, behavioural manifestations of executive impairment can often remain obscured by the structure and cues afforded by the assessment context. Consequently, some formal, psychometric assessments of executive functioning provide a very narrow and limited range of information regarding the individual’s ability to undertake activities within their day-to-day life. Despite the introduction of more ecologically valid tests this difficulty remains a significant one in relation to adequate assessment of executive functioning (Manchester et al, 2004 9). The clinician’s dilemma of predicting how a client might behave in their day-to-day life is made no easier by the elusive and variable nature of specific dys-executive problems including thinking/doing dissociations, impulsivity and high levels of variability in functioning secondary to context, structure and levels of support. Moreover, the patient’s limited awareness of their condition might reduce their likelihood of seeking out support, incorporating advice from others or applying their knowledge to new or different scenarios. The latter point takes on greater significance in the context of ‘Boreham’s principles’, underlining the common sense view that most of us do not have the capacity to independently manage all aspects of our affairs (White v Fell, 1987 - unreported). However, the patient’s insight, realisation that they have a problem and their ability to seek advice and to understand the same are relevant to the question of capacity. Some psychological assessments of capacity, whilst generally compliant with the MCA guidance, might fail to address these ‘meta cognitive’ aspects of the patient’s condition.

In view of these issues, many mental capacity assessments are therefore likely to need to include an informant, reference to broader functional/behavioural evidence and even multiple assessments. The need to include more detailed behavioural evidence in order to inform the assessment of capacity remains paramount and in the absence of this, an assessment is likely to prove parochial and fail to adequately represent vulnerability and incapacity secondary to changes in self-awareness, and reduced behavioural and emotional regulation.

The Vulnerability vs Incapacity conundrum

What we know matters but who we are matters more (Brene Brown)

As previously noted, a dearth of information relating to the patient’s beliefs, values, social context, support networks and environment may offer a parochial or skewed picture of the patient’s decision making abilities and capacity. For sure, the four tests of capacity (mirrored in the language and format of associated documents such as the COP3 form) can often serve to collude with the notion of mental capacity as a disembodied, internal computational ‘process’ devoid of history, discourse or social influence.

Judgements of when vulnerability becomes incapacity are multi-faceted and need to reference the patient’s ‘impairment of mind’ in its actual context. For example, the effect of social isolation for many younger patients is often to limit opportunities for experiential learning and increase the likelihood of undetected exploitation and abuse at both the financial and personal level. Moreover, the tendency for isolated patients to use financial resources to facilitate and maintain friendships will often serve to compound vulnerability. In short, differentiating between unwise and incapacitous decisions will often need to provide greater insight into not only the individual’s ability to effectively process key information but also their ability to recognise and evaluate social influences and pressures. This observation has increased relevance in light of the insidious role of social media in shaping thinking and associated, inconspicuous opportunities for vulnerable adults to be strategically or opportunistically exploited or abused.

Psychological Evidence and the next 10 years….

One of the things that has happened to us in the 20th Century as a human race is how to learn certainty crumbles in your hand. We cannot any longer have a fixed view of anything – the table we’re sitting next to, the ground beneath our feet, the laws of science, are full of doubt now. (Salmon Rushdie)

The clear implication of the House of Lords Review of the MCA is that the process of delivering on the MCA principles is likely to be complex and hard won. Lawyers, clinicians and other individuals and agencies involved in work with vulnerable adults will need to take time to reflect on the implications of the legislation, the associated professional guidance for how we work, obstacles to achieving best practice and the responsibilities incumbent upon us all. The British Psychological Society Interim Guidance (2006 10) has set out a framework, including a ‘functional approach’ to capacity assessment, placing emphasis on the individual within their unique situation and history. This approach stems from the tradition of psychological formulation as a modus operandi, where the integration of multiple sources of information provides the basis for a ‘working model’ of the patient’s condition, in contrast to one focussed on illness, classification or diagnosis.

Moreover, psychology may well occupy a unique position in terms of its potential to reflectively apply models of how patients think, including idiosyncrasy, contradictions and bias, to its own thinking and decision making processes. However, like many of other clinical groups, when faced with complex and risky patients we are also likely to default to the familiar, including the security of the consulting room, the illusory certainty of psychometrics and possible overconfidence in the objectivity and wisdom of our own decisions. If we are to represent the complexity and diversity of our patients and fully understand the vagaries of human decision-making we will need to ensure that we are referencing every facet of the person’s history, environment and social context. Moreover, psychologists could seek the position of ‘safe uncertainty’, or the ability to hold beliefs and knowledge with “authoritative doubt” – a balance of expertise and uncertainty (Mason, 1993 ). Correspondingly, our enquiry and exploration will be more likely to explore meaning than argue about facts, elevating curiosity and collaboration above certainty and ‘truth’. This approach would be entirely consistent with the imperative of explaining the complexity of the patient’s psychological functioning and decision making processes whilst upholding the ethos of empowerment and protecting the rights of vulnerable adults.


1, Select Committee on the Mental Capacity Act 2005. Report of Session 2013–14: Mental Capacity Act 2005: postlegislative scrutiny. London : The Stationery Office Limited

2, Social Care Institute for Excellence (2009). Mental Capacity Act 2005 at a glance.

3, Audit tool for Mental Capacity Assessments: The British Psychological Society Practice Board & Social Care Institute for Excellence, 2010.

4, Kapp, M.B., & Mossman, D. (1996). Measuring decisional capacity: cautions on the construction of a “capacimeter”. Psychology, Public Policy & Law, 2(1): 73-95.

5, Newby, H., & Ryan-Morgan, Assessment of Mental Capacity. In, Practical Neuropsychological Rehabilitation in Acquired Brain Injury (2013), Newby, G., Coetzer, R., Daisley, A., & Weatherhead, S: Karnac; London.

6, Brooks, B.L, Iverson, G.L, Holdnack, J.A. (2009) Understanding and Using Multivariate Base Rates with the WAIS–IV/WMS–IV. Advanced Clinical Interpretation, 75- 102

7, Dr Graham Powell, Presentation at BPS Conference. The cognitive psychology of decision-making with respect to assessing mental capacity. 28th April 2015

8, Hovland, Carl I.; Sherif, Muzafer (1980). Social judgment: Assimilation and contrast effects in communication and attitude change. Westport: Greenwood.

9, Manchester, D., Priestley, N. & Jackson, H. (2004), The assessment of executive functions: coming out of the office. Brain Injury, 18 (11): 1067-1081.

10, BPS Interim Guidance on Assessing Capacity in Adults (2006). Available from www.bps.org.uk

Richard Maddicks

Richard has worked in neuro-rehabilitation in both the NHS and independent sector since his doctoral qualification in 1996. 20 years experience in medico-legal work has seen him instructed as an expert neuropsychologist in many diverse and complex civil, criminal and family law cases. However, his strong interest in rehabilitation and treatment has also underpinned an emphasis on therapeutic work with patients following trauma, mild brain injury and other complex and severe neuropsychological presentations.

Richard formed Psychology Chartered over 10 years ago and it is now an established independent provider with a reputation for its accessibility, efficiency and clinical expertise.



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