Unfitness to Plead, Insanity and the Law Commission: Do We Need a Diagnostic Threshold?

This article examines one aspect of the new test of effective participation at trial proposed by the Law Commission of England and Wales. This proposal aims to replace the current criteria for fitness to plead originating from Pritchard and developed more recently in M (John). Specifically, this article offers a critical examination of the Commission’s refusal to incorporate a so-called ‘diagnostic threshold’ within their proposed test. After reviewing the arguments for and against this decision, attention is drawn to the clear presence of diagnostic thresholds within other areas of law, such as the mental condition defence of insanity. Overall, the Commission’s proposals are a vast improvement upon the archaic rules of present day, and, contrary to the views of some scholars, their decision to omit a diagnostic criterion is no exception to this. In fact, the implications of this decision reach far beyond the particular context of unfitness proceedings and ultimately cast doubt on the significance of diagnostic thresholds in all areas of law. By focusing exclusively on the relationship between unfitness to plead and the defence of insanity, this piece demonstrates how both tests can be reformulated so as to avoid any explicit reference to a diagnostic criterion.


Introduction
The law relating to unfitness to plead should exempt an individual from a criminal trial, either permanently or temporarily, when he is considered incapable of comprehending and meaningfully participating in court proceedings. 1 Some may disagree with this statement by arguing that, irrespective of a defendant's fitness, a trial should always proceed as normal. For instance, advocates for victims may cite the necessity of 'closure' and the importance of the victim's voice being heard. 2 Nevertheless, it is submitted that the initial position-that the law should exempt an unfit defendant from a criminal trialis to be preferred. This is because the notion of proceeding with a trial regardless of a defendant's fitness would be an abuse not only of their individual rights but also of the rule of law. 3 As Brown opines, '[i]f a defendant cannot properly defend themselves, it could lead to inaccurate or unjust verdicts and, at worst, imprisonment for an offence which they did not commit'. 4 In the end, the purpose of fitness-to-plead laws is twofold: to balance the rights of vulnerable defendants with the need to protect the public and to balance natural justice with the desire to see justice served. 5 In 2016, the Law Commission of England and Wales published their final report concerning their recommendations arising from a six-year consultation into fitness to plead. 6 The Commission propose that the current common law criteria for determining an accused's fitness should be replaced with a new statutory test aimed at establishing whether the defendant lacked the 'capacity to participate effectively' with the trial process. 7 This article offers a critical examination of one element that is noticeably missing from the Commission's proposed test; specifically, a 'diagnostic threshold'. In other words, the Commission were not in favour of requiring a link between the lack of capacity and, for example, a recognised medical condition-preferring instead to prioritise the lack of capacity itself as the sole determinative factor. 8 The Commission's refusal to explicitly incorporate such a threshold is consistent with the current law on unfitness, as governed by the case of Pritchard. 9 However, their decision continues to render this area anomalous in comparison to related sectors of law, such as the mental condition defences, 10 and the civil law criteria of decision-making capacity encompassed within the Mental Capacity Act (MCA). 11 After initially presenting the arguments in favour of including a diagnostic threshold within the fitness-toplead framework, the article dedicates significantly more attention in the latter half to critically reviewing the persuasiveness of the preceding submissions. Ultimately, it is proposed that the Commission were correct to exclude such a requirement. It is conceded that this conclusion has important implications for the aforementioned areas of law, since, if it is preferable for unfitness to exclude a diagnostic requirement, then why should insanity, the MCA or diminished responsibility be drafted any differently? By focusing exclusively on the relationship between unfitness to plead and the defence of insanity, this article demonstrates how both areas can be reformulated so as to exclude any explicit reference to a diagnostic criterion. 12 2. N Padfield, '"Prosecuting" Those Who Are Unfit to be Prosecuted?' [2016]

The Current Law and the Commission's Proposed Alternative
Originating from Pritchard 13 and developed more recently in M (John), 14 an accused will currently be found unfit to plead if he presents an inability in one of six ways: 1. understanding the charges; 2. deciding whether to plead guilty or not; 3. exercising his right to challenge jurors; 4. instructing solicitors and counsel; 5. following the course of proceedings; 6. giving evidence in his own defence. 15 Evidently, this test addresses cognitive criteria, inquiring whether the accused has a basic understanding of the trial process. 16 This disproportionate emphasis on cognitive abilities was the primary focal point of concern for the Law Commission, who commented that the test only covers 'extreme cases of a particular type (usually bearing on cognitive deficiency)', 17 and fails to sufficiently address an accused's capacity for rational decision-making. 18 Thus, so long as a defendant has the intellectual ability to comprehend the basics of a trial process, he is unlikely to be found unfit under the M (John) criteria. 19 Concerningly, this may fail to capture the defendant who is suffering from a delusional disorder that impacts upon his capacity to make rational decisions which are in his own best interests. 20 The latest alternative proposed by the Law Commission is a combination of decision-making capacity and the current M (John) criteria: A defendant is to be regarded as lacking the capacity to participate effectively in a trial if the defendant's relevant abilities are not, taken together, sufficient to enable the defendant to participate effectively in the proceedings on the offence or offences charged. 21 The Draft Bill further provides a non-exhaustive list of abilities relevant to the assessment of capacity. 22 If implemented, the proposed test is likely to lower the threshold for unfitness, 23 and it is estimated that the number of defendants found unfit to plead will double as a result. 24 Undoubtedly, these recommendations have been broadly welcomed as a vast improvement upon the archaic rules of present day. 25 Interestingly, however, the Commission did not propose that any changes be made to the lack of a diagnostic threshold within the current Pritchard/M (John) criteria. Rather, they were 'squarely of the view' 26 that a reformed test of unfitness should continue to conform to the current law in this respect. As will be discussed, such a view is not without its supporters, 27 nor its critics. 28 The following sections will 13. Pritchard (n 9). 14. critically examine the arguments for and against the inclusion of a diagnostic threshold within the fitness-to-plead framework, before turning to address the author's own deductions on the matter.

Arguments in Favour of a Diagnostic Threshold
There are compelling practical reasons for why a reframed test of unfitness should include a diagnostic threshold, ie a requirement that the defendant be found to have a diagnosis of disorder, or some other qualifying condition, before he can be said to lack the capacity for effective participation. 29 For instance, when referring to one of the Commission's earlier proposals which similarly omitted such a criterion, Howard questions whether this provision may permit an individual claiming 'stress, crippling shyness, overwhelming tiredness, nervousness, or poor social background to escape a full trial?' 30 It is interesting to note that Howard's concerns regarding the potential breadth of an unfitness test are not novel. Indeed, similar views were expressed by the late-Victorian prison doctor, Hamblin Smith, who asked: How many prisoners are capable of making what may reasonably be called a 'proper defence', or of giving proper instructions for their defence? But surely it is clear that mere ignorance, or lack of education, or ordinary stupidity, should not be enough to justify a verdict of unfitness to plead. 31 The crux of the preceding statements is the desire to place appropriate parameters on findings of unfitness/lack of capacity. 32 Accordingly, a qualifying diagnosis may help to ensure that such a test is not impracticably wide.
In a similar vein, it can be said that the presence of a diagnostic threshold may add objectivity to the fitness criteria. For instance, a finding that a defendant suffers from paranoid psychosis at the time of the trial may add objectivity, and thus reliability, to the conclusion that he lacks the capacity to meaningfully participate in court proceedings. 33 As Morse opines, '[o]ne could jettison the mental disorder criterion in mental health laws, but the presence of a mental disorder allegedly provides an "objective marker" which shows that the person genuinely lacks the required rational capacity'. 34 In this sense, mental/ physical disorder may not so much add another requirement as add objectivity to the other criteria. Evidently, adding reliability to capacity-based assessments is also heavily intertwined with the desire to prevent malingerers from being erroneously deemed unfit to plead. 35 The validity of the preceding concerns will be examined in the subsequent part of this article. For present purposes, alternative reasons have been suggested for why the law should insist on a medical condition as a prerequisite for unfitness; reasons which have less to do with maintaining practicality and ensuring public protection and are more aligned with safeguarding an individual's right to legal capacity.
Ever since the passing of the Human Rights Act 1998, the need to safeguard individual rights gained prominence. In particular, ensuring the right to a fair trial under art 6 of the ECHR inevitably resulted in scrutinisation of the fitness-to-plead framework. 36 Anticipating these issues, the starting point of the Law Commission's recommendations is that a normal trial should proceed wherever possible and that removing a defendant from that process should be an option of 'last resort'. 37  ie that a defendant is presumed to be fit to plead until the contrary is proven, 38 and by expanding the availability of 'special measures', which potentially allow an otherwise unfit defendant to exercise their legal capacity in a normal and fair trial. 39 Nonetheless, the Commission concede that 'there will be a small group of defendants who will be unable to participate effectively in a trial, no matter the level of support provided to them'. 40 A defendant's right to a fair trial may be breached if the current law is unable to accurately distinguish those who can participate meaningfully in a trial from those who cannot. This may occur when a defendant who is unfit to plead is erroneously deemed fit to plead. But it may also occur when a defendant who is truly fit to plead is deemed unfit to plead. This could inevitably lead to a situation in which an accused is erroneously treated as if they lack the capacity for effective participation. Accordingly, depriving a defendant of the most fundamental right to stand trial is a decision which ought to be robustly defensible.
The discussion above shares much similarities with Howard's most recent position on the suitability of a diagnostic threshold for fitness-to-plead laws. Howard refers to the theoretical concept of 'moral agency', 41 which she argues 'should be present not only at the time of committing the act, but also at the time of standing trial'. According to the leading theory of culpability-known as choice (or capacity) theory-only a defendant who possesses the capacity and a fair opportunity to make choices is able to be tried and held accountable for his actions. 42 Lacking capacity is certainly one way in which a vulnerable defendant may cease to be a moral agent. More specifically, Howard asserts that we must be 'sure of our reasons' before depriving an individual of this agency, especially since the accused will be deprived of his fundamental right to a fair trial. 43 She proposes that requiring a link between the lack of capacity and a recognised medical condition would provide 'support for those reasons', 44 thereby ensuring that the law enables a defendant to exercise their legal autonomy in all but the most justified of cases.
Seemingly influenced by the previous concerns, the test for unfitness to plead currently adopted in Scotland requires the defendant to be incapable, by 'reason of a mental or physical condition', of participating effectively in a trial. 45 Virtually identical provisions have also been incorporated into the jurisdictions of Jersey, 46 Canada 47 and New Zealand. 48 Consequently, within these jurisdictions, inabilities in themselves do not constitute incompetence to stand trial; these inabilities must be the result of a mental/physical impairment.
Finally, as alluded to above, it may be added that the presence of a diagnostic threshold would promote consistency, and thus greater certainty, throughout both civil and criminal law. In civil law, the MCA, which deals with a person's decision-making ability, requires an impairment of, or a disturbance in the functioning of, the mind or brain. 49 This defect must result in an inability to understand, retain, use or weigh information relevant to a decision, or to communicate a choice, 50 for that person to lack capacity. Once again, inabilities in themselves do not constitute incompetence; they must result from a defect in the mind/brain. In the criminal law context, the same is true for the mental condition defences of insanity and diminished responsibility. defendant to suffer from a 'disease of the mind' which caused him not to know the nature and quality of the act or that it was legally wrong. 51 Interestingly, when the Commission proposed reform recommendations for the defence of insanity in 2013, they chose to retain a diagnostic threshold. 52 To satisfy their new defence, the party seeking to raise it must establish that the defendant wholly lacked the capacity to: i. rationally form a judgment about the relevant conduct or circumstances; ii. understand the wrongfulness of what he or she is charged with having done; or iii. control his or her physical acts in relation to the relevant conduct or circumstances as a result of a qualifying recognised medical condition. 53 As such, while the Commission have clearly altered the criteria within the defence, they have retained the requirement of a diagnostic component-merely substituting 'disease of the mind' for 'a qualifying recognised medical condition'. Howard logically purports that if a diagnostic threshold is contained within other areas of law-such as insanity-then 'compelling reasons should exist' for why it should not be required for unfitness. 54 Alternatively, however, it can equally be suggested that neither unfitness nor insanity should require such a threshold. The remainder of this article intends to address this latter proposal by drawing upon the work of scholars who have criticised the diagnostic criterion. It will become clear that the vast majority of critiques can be applied across both contexts. Thus, an argument opposing a threshold for the insanity defence is also an argument against a threshold for unfitness-and vice versa.

Arguments Against the Inclusion of a Diagnostic Threshold
Primarily, the Commission have omitted a diagnostic criterion from their test of unfitness in order to ensure the test is broad enough to encompass all potential reasons for participation difficulties. 55 In other words, because there are a myriad of ways in which a defendant could lack the capacity for effective participation, it may be difficult to draft a diagnostic threshold that could easily account for all of them. 56 In turn, some defendants may be unfairly deemed as fit to plead simply because their particular condition escapes definition. Furthermore, the Commission commented that, 'we doubt whether imposing a diagnostic threshold would be likely to assist in maintaining the threshold of unfitness at a suitable level'. 57 Thus, if a diagnostic threshold were capable of a suitable definition (ie it were so widely drawn as to encompass all possible barriers to participation), 58 it would ultimately make no difference to the test. 59 In order to further substantiate the reasoning of the Commission, it is worth examining the work of scholars who have comparably advanced the removal of diagnostic-based criteria from the mental condition defence of insanity. Within this context, the philosophers Matthews 60 and Vincent 61 have both notably proposed an incapacity-based, rather than a mental disorder-based, approach to criminal responsibility. According to these writers, it is morally irrelevant whether certain incapacities were brought about by mental disorder, or by any other condition. Therefore, the reference to 'disease of the mind' in the M'Naghten Rules, or to a 'recognised medical condition' within the Law Commission's proposals, should be omitted. If such references are removed, the term 'insanity' would no longer be an appropriate label. Instead, the relevant defence would simply be one of incapacity. 62 Matthews initiates his argument with a straightforward thought experiment. Suppose a very young child, Ben, is playing on a freeway overpass and 'gleefully throws rocks over a wall and into the path of oncoming traffic. A fist-sized rock smashes through the windscreen of a vehicle and seriously injures the occupant'. 63 Ben will, of course, not be blamed. But why? The simple reply is that Ben is not responsible because he is only a child; but Matthews is dissatisfied with this response. In essence, he argues that there is a deeper reason for not holding Ben-and young children in general-responsible for their conduct. For Matthews, the rationale behind exculpation is that they lack the capacities required for being held a morally responsible agent. 64 This ties in well with Howard's assertions regarding the importance of moral agency to trial and responsibility. 65 The same is true for cases of insanity: moral responsibility is withheld because of the lack of relevant capacities on the part of the defendant. 66 Taking the example of the Commission's newly proposed test for insanity, if a defendant lacks the capacity to form a rational judgment, to understand the wrongfulness of his actions, or to control his behaviour, then surely the lack of capacity itself should be sufficient to negate responsibility. It is compelling to question just why we really need to know that such an incapacity resulted from a mental disorder.
Along the same lines, Vincent argues that mental disorder is 'neither necessary nor sufficient for reduced responsibility'. 67 First, by comparably referring to children, she states: '[t]hat disorder is not necessary for reduced responsibility is plain when we consider young children-a group whose responsibility is negated despite the absence of a clinically recognised disorder'. 68 Furthermore, Vincent argues, mental disorder is not sufficient for reduced responsibility either. This is because the mere existence of a mental disorder is not sufficient to exculpate a defendant under current insanity standards. Rather, they all additionally require the influence of the disorder on the defendant or the relevant act, such as causing one to not know that the act was wrong. 69 This is understandable. After all, an insanity test which merely required the presence of a mental disorder (such as psychosis) would be open to the challenge that it suggests psychotic people are generally not responsible for their actions and may also contribute to stigma of those who suffer from this disorder. In brief, tests for legal insanity are virtually never phrased so as to exempt individuals from responsibility solely because they are mentally ill. 70 As such, Vincent succinctly concludes by declaring that 'capacity and not disorder is what determines responsibility'. 71 Evidently, an explicit diagnostic criterion-whether for unfitness or insanity-would be otiose if defendants who lack the requisite capacity will always suffer from a diagnosable medical condition. 72 There is certainly room for argument about this. After all, an incapacity is a 'condition' and could be argued to be a medical condition in the sense that it is the kind of condition in which doctors (whether 62 physical or psychiatric) have a clear interest: being incapacitated, in a way that undermines the ability to lead an ordinary or normal life, is a way of lacking health-of being ill, disordered or deficient. Theoretically speaking, however, it is perhaps possible that a defendant may satisfy the latter half of the test (lacking capacity) and fail the former (having a relevant mental/physical disorder). 73 This is the view of the Commission within their discussion paper on insanity. They argue that a diagnostic threshold is not superfluous; indeed, they contemplated cases in which a defendant wholly lacks one of the three capacities relevant to their recommended test, but the defence fails because the incapacity cannot be attributed to a 'qualifying recognised medical condition'. 74 For instance, the Commission opine that 'any condition which is manifested solely or principally by abnormally aggressive or seriously irresponsible behaviour' should not count as a 'qualifying' recognised medical condition. The concern here is with antisocial personality disorders, in particular, psychopathy. Those who believe that psychopathy can (or should) exempt an accused from criminal liability typically argue their case on the grounds that such a condition may substantially diminish or even destroy a relevant rational capacity. 75 This author does not intend to enter the discussion here, merely to point out the opinions of others who have argued in favour of this view of the disorder. To summarise, it is difficult to see what could possibly justify the conviction of a person who utterly lacked the capacity to conform his conduct to the requirements of law; precisely how this incapacity originated should be irrelevant. 76 Furthermore, even if, in practice, defendants who lack the relevant capacities will always suffer from a recognised medical disorder, this does not necessarily mean that the legal test could not simply be phrased in terms of the detrimental effects of these disorders, ie incapacities. 77 Matthews helpfully demonstrates how an insanity standard can be rephrased in such terms by using the Australian legal context-the Commonwealth Criminal Code Bill 78 -as an example: A person is not criminally responsible for an offence if, at the time he or she carried out the conduct constituting the offence, he or she failed the test of responsible agency. This test is failed if any one of the following three conditions is satisfied: (a) the person lacked the capacity to understand the nature of what he/ she was doing; (b) the person lacked the capacity to understand that what he/she was doing was wrong; or (c) the person lacked the capacity to control his/her conduct. 79 In essence, Matthews has replaced the criterion of 'a mental impairment' with that of 'failed the test of responsible agency', which is understood in terms of three incapacities. As we shall see, there is no reason why a similar revision could not also take place within the M'Naghten Rules, or the Commission's newly proposed 'recognised medical condition' defence.

A Critical Review of the Arguments in Favour
Nonetheless, these more conceptually oriented arguments may still fail to sufficiently outweigh the compelling practical concerns which are commonly advanced by those in favour of diagnostic criteria. The principal argument of these proponents is that such a threshold adds, in the words of Morse, an 'objective marker' 80  that we must be 'sure of our reasons' 81 before depriving an individual of their capacity and that a diagnostic threshold strengthens and 'supports' 82 our reasons in this respect. It is this author's view that the concerns of both Howard and Morse are inextricably linked. In other words, if a diagnosis of disorder truly adds objectivity/reliability to a finding of incapacity, then, contemporaneously, such a diagnosis also helps us to be sure of our reasons for wishing to deprive that individual of their legal capacity.
Consequently, for those who would advocate the explicit presence of a diagnostic requirement, much of their argument seems to hinge on the degree of objectivity that such a criterion adds. It is arguable, however, that diagnosis is not as objective as some scholars would appear to make out. This dilemma has been considered by Meynen, who asks the reader to consider depression, anxiety and craving-all of which are subjective states: Generally, psychopathological core symptoms and phenomena are only immediately accessible from a firstperson perspective. I (first person) feel depressed. Such a depressive state is not immediately accessible to other individuals, e.g. to a psychiatrist or psychologist. This is different from a broken leg: although I am in pain, the brokenness of that leg is clearly objectifiable for others. Subjective symptoms, in contrast, must be reported by the patient. 83 Indeed, a DSM-informed psychiatric diagnosis is based primarily on self-reports of feelings and experiences by patients and on clinicians' understanding of psychiatric terms or observation of behaviour. Clearly, there are also more objective elements of DSM-criteria, such as weight loss in depression. 84 Nevertheless, it cannot be denied that subjectivity (and, thus, unreliability) plays an important role in diagnosing mental disorders and establishing the 'objective marker' to which Morse refers. Indeed, this inevitable lacuna is conceded by Morse himself, who, after initially asserting that diagnostic thresholds act as an 'objective marker', subsequently states 'it achieves this goal only imperfectly at best'. 85 Moreover, it may be said that if the sole purpose of a diagnostic requirement is merely to add objectivity to a finding of incapacity, it need not become an explicit criterion in itself. It may be part of the relevant medical expert's explanation of why the defendant meets the criteria, and it may also be helpful in persuading a court that the defendant legitimately does lack the requisite capacity, but it need not be a criterion of its own. 86 The Law Commission appear to express somewhat similar thoughts within their report on unfitness to plead, when they state that the absence of a diagnostic threshold 'does not prevent diagnosis from being an important part of capacity-based assessments, a helpful guide to identifying malingering, and a tool for predicting future recovery'. 87 In legal practice, it might be hypothesised that a judge/jury will only accept that a defendant meets the criteria if the medical expert has diagnosed and clarified how the particular disorder affected the criteria of capacity. 88 Regardless of whether this hypothesis turns out to be true, it remains difficult for a court to make a determination on a defendant's lack of capacity without the evidence of relevant medical experts. As cl 2(1) of the Commission's Draft Bill provides: illness offers a special reason for concluding that this incapacity is responsibility-undermining. 97 Deleting the diagnostic threshold from insanity formulations may therefore threaten to confuse the relationship between insanity and mistake of law.
While it is true that a large number of defendants may be able to claim, successfully, that they did not know their conduct was prohibited by law, it would be incredibly difficult for them-without a recognised illness-to convince a court that they lacked the capacity to know the law. Nevertheless, if such a deficit can be robustly proven, irrespective of a recognised illness, then it seems unfair and arbitrary to exclude such a person from relying on the insanity defence. 98 To summarise, it is once again submitted that this suggestion fails to provide sufficient grounds for insisting on the presence of a diagnostic threshold as a legally formal criterion: indeed, diagnostic thresholds are either entirely otiose or demonstrably unfair.
Before concluding, it is worthwhile noting an alternative suggestion made by Duff regarding the issue of prior fault. Specifically, Duff suggests that the Commission viewed the inclusion of a diagnostic criterion as appealing because it would help to prevent cases of prior fault from wrongfully falling under the defence. Duff correctly purports, however, that this rationale is flawed for two crucial reasons. First, the conditions that the Commission provisionally propose should not qualify for the defence, such as 'acute intoxication or any other condition which is manifested solely or principally by abnormally aggressive or seriously irresponsible behaviour', are not necessarily caused by the person's own culpable prior conduct. 99 And second, any 'recognised medical condition' could, in principle, be caused by the person's own culpable prior conduct. 100

Conclusion
The preceding discussion has demonstrated that the arguments in favour of including an explicit diagnostic threshold do not appear persuasive when subjected to a thorough critique. While it is conceded that diagnosis has the potential to grant a limited amount of objectivity to the remaining criteria, and will continue to play an important role in psychiatric assessments, an explicit diagnostic requirement is not necessary to achieve these aims. Consequently, it is submitted that the approach taken by the Law Commission within their final report on unfitness to plead is to be preferred. Of course, such a position raises issues with regard to consistency, given that the custom in other areas of law is to incorporate an explicit diagnostic criterion within the relevant test. Perhaps the alleged 'objectivity' that such a threshold provides is more important when establishing a person's criminal responsibility, rather than their ability to stand trial. Nevertheless, the conventional approach is not always the most appropriate. In fact, concerns regarding the presence of a diagnostic threshold are not novel and have been equally advanced within the context of the insanity defence. This article has ultimately proposed that both areas-unfitness and insanity-should be reformulated so as to avoid any explicit reference to a diagnostic criterion.
For unfitness to plead, the current law and the Law Commission's proposed alternative omit a diagnostic requirement. It is stipulated, however, that the latter test should be preferred due to the numerous improvements it makes by bringing the law more into line with modern psychiatric and psychological knowledge. In stark contrast, the current insanity defence and the Commission's proposed alternative both include a diagnostic requirement. It is unfortunate the Commission chose to retain this 97