Volitional Insanity: Involuntariness, Injustice and Cognitive Impairment

Chapter 5
Volitional Insanity: Involuntariness, Injustice and Cognitive Impairment

Introduction

In this chapter I will argue that an individual may suffer from a mental disorder which will allow him or her to know the nature, quality and wrongness of his or her act and yet nevertheless be precluded from acting voluntarily. I will argue that where an accused’s lack of capacity to act voluntarily arises independently of a cognitive defect but is due to a mental disorder that is characterized as a disease of the mind, the defence of insanity should be available. That is, where an individual who suffers from a disease of the mind is rendered incapable of voluntary conduct, even where he or she knows the nature and wrongness of his or her act, the defence of insanity should be acknowledged at common law.

As will be set out below the extent to which involuntary conduct arising from mental disorder is recognized as a disease of the mind in order to ground the defence of insanity varies amongst Australian jurisdictions.¹ In particular, while most code jurisdictions have a separate volitional limb added to their insanity defence, the common law has not treated involuntary conduct arising from mental disorder as an independent limb of the insanity defence. Moreover, endeavours to broaden the defence at common law in order to allow volitional disorders to ground the defence have, with certain exceptions which are discussed below, not been successful.

The present discussion is motivated by the view that the refusal of the common law to recognize states of volitional impairment without any cognitive impairment as sufficient to ground a defence of non-responsibility may result in the punishment of morally innocent individuals. Individuals who lack the capacity for voluntary conduct due to mental disorder lack the capacity for responsible action and, by implication, cannot be deterred by the threat of punishment. Hence, in punishing such individuals the law, I would argue, is in fact punishing the morally innocent. Nevertheless, certain commentators have maintained that the common law’s failure to recognize an independent volitional limb as sufficient to ground an insanity defence does not result in injustice as all instances of involuntary conduct arising from mental disorder involve some form of cognitive impairment.

Insanity and involuntary conduct

The centrality of voluntariness to criminal liability is recognized in both common law and code jurisdictions as a matter of legal principle.² Doctrinally it is said that all criminal conduct requires proof of a physical element. The physical element of criminal conduct must be performed voluntarily. Conduct is only voluntary where it is the product of the will of the person performing the conduct.³ For example, under the criminal codes of Queensland and Western Australia a person is not criminally responsible for ‘an act or omission’ occurring ‘independently of the exercise of the person’s “will”’.⁴ Consequently, under the codes an accused is not responsible where his or her act occurs independently of his or her will.

The High Court in R v Falconer⁵ has held that the requirement under the Western Australian Code that an accused’s conduct be the result of the exercise of his or her will in order for him or her to be held criminally responsible is the same as the common-law requirement for conduct to be voluntary. As expressed by Mason CJ, Brennan and McHugh JJ:

Mrs Falconer is criminally responsible for discharging the gun only if that act were ‘willed’, that is, if she discharged the gun ‘of [her] own free will and by decision’ (per Kitto J in Vallance at 64) or by ‘the making of a choice to do’ so (per Barwick CJ in Timbu Kolian at 53). The notion of ‘will’ imports a consciousness in the actor of the nature of the act and the choice to do an act of that nature.⁶

Where a person’s conscious mind directs an act, he or she does the act by will or choice. In such a case a person makes a decision to engage in particular conduct.

Unwilled conduct may occur in several different ways. For example, the Commonwealth Criminal Code states that:

(3) The following are examples of conduct that is not voluntary:

‘a spasm, convulsion or other unwilled bodily movement; an act performed during sleep or unconsciousness;

an act performed during impaired consciousness depriving the person of the will to act’⁷

Where an accused’s mental disorder is characterized as a disease of the mind and results in involuntary conduct he or she is obligated to raise a plea of insanity rather than involuntariness.⁸ In pleading the insanity defence an accused is debarred from an outright acquittal and is, subject to what is to be outlined below, a candidate for a qualified acquittal.

To the extent that a finding of insanity results in a qualified rather than outright acquittal the disposition of an accused whose act is involuntary due to a disease of the mind represents a departure from the above mentioned general principle of criminal liability. Such a departure from the general principle of voluntariness as a necessary element of criminal liability is necessitated by a policy concern with societal protection it being incumbent on the law to protect the community from ‘dangerous’ people.⁹ As noted in Chapter 2, the dispositional aspect of the disease of the mind enquiry seeks to ensure social-defence considerations receive appropriate attention whenever there is a finding of insanity. Consequently, individuals suffering from a disease of the mind are considered to be appropriate targets of therapeutic intervention rather than punishment. In this way both the individual’s and society’s interests are served: the former by being provided with appropriate treatment the latter by ensuring that such an individual is, where needed, kept in a secure facility.

However, having raised the issue of insanity, it is incumbent on the accused to satisfy the requirements of the defence on the balance of probabilities.¹⁰ In particular, the accused must show that the nature of the mental malfunctioning arising from the state of mental impairment (disease of the mind) is one that is, depending on the jurisdiction, recognized by the M’Naghten rules¹¹ or a statutory formulation of the insanity defence.¹²

Under the current law where an accused seeks to raise a defence of non-responsibility on the basis of involuntariness resulting from mental disorder there are two matters that warrant notice: the first concerns the displacement of principle by policy; the second, the requirement on the part of the accused to satisfy the elements of the defence as stipulated in the relevant jurisdiction. This results in the counter-intuitive position that not only is a volitional disorder precluded from giving rise to an outright acquittal, but also in order for an accused to obtain a qualified acquittal, he or she must ensure that the nature of the resulting malfunction arising from his or her mental disorder is one which is recognized as an incapacitating condition by the defence of insanity in the relevant jurisdiction. This may prove problematic where an accused’s mental disorder results in involuntary conduct and the relevant jurisdiction defines the requisite incapacitating conditions of the defence of insanity restrictively so as not to include states of involuntariness. Involuntary conduct arising from mental disorder is not a recognized limb of the defence of insanity at common law. However, the common law has endeavoured to take into account an accused’s incapacity to control his or her conduct in establishing the defence of insanity. This will be considered further in the following section. In contrast to the common law, code-jurisdiction formulations provide an explicit volitional limb in respect of an accused’s incapacity to control his or her actions. This will be considered further in the section after.

Notwithstanding the above, courts have endeavoured to ensure a more liberal interpretation of the defence for the benefit of defendants experiencing involuntary conduct arising from mental disorder. In particular, courts will characterize an accused’s involuntary conduct arising from mental disorder as evidence of a lack of the requisite kinds of knowledge required to ground a defence of insanity at common law. This is the approach adopted in most common-law cases.¹³

A more radical approach which has been adopted by courts on occasion is to reject the current scope of the insanity defence and hold that a volitional disorder should be recognized as an independent limb of the insanity defence sufficiently incapacitating for the purposes of the defence. Such an expansionary approach has been applied in some common-law cases.¹⁴

Volitional disorder: evidence of defect of reason

At common law, involuntary conduct arising from a mental disorder may only be used as evidence of insanity, it will not establish the defence of insanity.¹⁵ As Dixon J observed in Sodeman v R:

If [the accused] is able to understand the nature of his [or her] act and to know that the act is wrong, an incapacity through disease of the mind to control his [or her] actions affords no excuse and leaves the prisoner criminally responsible.¹⁶

Similarly, Latham CJ stated that:

The direction explains that uncontrollable impulse in itself is not a defence, but that uncontrollable impulse resulting from mental disease which brings about or is associated with an incapacity to know the nature and quality of an act or to know that it is wrong amounts to insanity which constitutes a defence. In my opinion this is an accurate state [sic] of law. Such an impulse may be one manifestation of mental disease. It may have the effect of destroying or preventing knowledge of the nature and quality of the act done or knowledge that the act is wrong. In such a case, insanity is established, but by reason of the latter feature of the case and not by reason of uncontrollable impulse per se. This principle of law is frequently criticized, especially by medical and other scientific men, but a Court must administer the law as it finds it.¹⁷

Consequently, the fact that there is a volitional disorder characterized as a disease of the mind will not, at common law, give rise to an insanity defence unless such a disorder precludes the accused from knowing either the nature and quality or wrongness of his or her act. Where an accused establishes the requisite absence of knowledge he or she will receive a qualified acquittal. Where an accused fails to establish the requisite absence of knowledge the defence will not be available and he or she will be convicted.

However, while there is no recognized common-law defence of involuntary conduct arising from mental disorder, courts have been prepared to consider the evidentiary import of a range of mental disorders by recognizing that one type of mental disorder may provide evidence of the existence of another.¹⁸ For example, rather than being considered to be instances of mutually exclusive types of malfunctioning, evidence of involuntary conduct arising from mental disorder has been held to lend support in establishing a state of cognitive impairment and thereby satisfy the requirements of the M’Naghten rules. This section will consider two High Court cases in which the court has viewed an accused’s involuntary conduct arising from a mental disorder as evidence of a state of cognitive impairment which will satisfy the defence of insanity. In Sodeman, Dixon J noted that:

It is important to bear steadily in mind that if through disorder of the faculties a prisoner is incapable of controlling his relevant acts, this may afford the strongest reason for supposing that he is incapable of forming a judgment that they are wrong, and in some cases even of understanding their nature.¹⁹

Sodeman makes it clear that involuntary conduct arising from a mental disorder may provide evidence as to both an accused’s incapacity to know the nature of his or her act, as well as his or her incapacity to know that an act is wrong.

The evidentiary approach adopted in Sodeman has found subsequent support in the High Court case of Brown v A-G (SA) where it was stated that: ‘Uncontrollable impulse … may afford strong ground for the inference that a prisoner was labouring under such a defect of reason from disease of the mind as not to know that he [or she] was doing what was wrong’.²⁰ However, the claim that various types of mental disorder may be symptomatic of one another falls short of establishing that involuntary conduct arising from mental disorder, independent of the operation of a cognitive defect, will provide exculpation. That is, the approach adopted in both Sodeman and Brown remains hostage to the psychiatric facts being a certain way. In particular, on the Sodeman/Brown approach, a defence will be available to an accused only where the accused’s disease of the mind gives rise to involuntary conduct and such involuntary conduct is accompanied by a lack of knowledge as to the nature or wrongness of his or her act.

However, notwithstanding the use to which the evidentiary approach has been put, the M’Naghten rules have been criticized by various courts as failing to provide a sufficiently comprehensive test of insanity.²¹ Yet, any detailed discussion of the type of mental malfunction that may satisfy the M’Naghten rules should be cognizant of a comprehensive range of mental disorders.²² On its face there is no reason to believe that, as per Sodeman and Brown, the only varieties of mental malfunction which may be experienced by an accused are those where an accused’s involuntary conduct is accompanied by a lack of knowledge. For example, a psychiatric condition may be envisaged wherein the accused knows that his or her act is wrong, yet he or she is not able to act voluntarily. In fact, psychiatric diagnostic manuals have tentatively recognized such states with discrete diagnostic categories. In such instances an accused’s involuntary conduct may be viewed as occurring independently of his or her lack of knowledge as to the nature or wrongness of his or her conduct. One such category, pyromania, will be discussed below. In the light of the clinical recognition of such a state, common-law courts have on occasion endeavoured to accommodate involuntary conduct arising from mental disorder by acknowledging a defence of insanity arising from a state of volitional disorder independent of the M’Naghten rules’ knowledge requirement. Several such cases will be considered in the next section.

Case law: expansionary developments

Certain jurisdictions, such as Ireland and South Africa, which have adopted the M’Naghten rules have considered them to be non-exhaustive pronouncements of the law and have judicially recognized involuntary conduct arising from mental disorder as sufficient to ground the defence of insanity.²³

An example of a case in a common-law jurisdiction which seeks to recognize involuntary conduct arising from mental disorder as an independent ground for the defence of insanity is to be found in the Supreme Court of Ireland case of Doyle v Wicklow County Council.²⁴ In Doyle a 17-year-old boy had deliberately burnt down an abattoir intending to destroy both the premises and contents. Medical evidence established that the accused was suffering from a mental disorder which prompted him to set fire to the premises as a means of protest against the slaughter of animals in the belief that he was justified in so doing, although he knew his act to be forbidden by society or contrary to law.²⁵

The Supreme Court in Doyle recognized that a defendant may know that his or her act is wrong, yet nevertheless be held to satisfy the requirements of the defence on the basis of involuntary conduct arising from a disease of the mind. Griffin J, in delivering the judgment of the court, specifically noted that, on the facts, it was the ‘capacity of a man on the basis of his knowledge to act or refrain from acting’ that was in issue.²⁶ As put by Griffin J, the key issue in Doyle was whether mental disorder precludes a defendant’s capacity ‘to act or refrain from acting’ notwithstanding his knowing what he is doing and that it is wrong.²⁷ That is, unlike the High Court of Australia in Brown, the Supreme Court of Ireland in Doyle did not view involuntary conduct arising from a mental disorder as merely symptomatic of an absence of knowledge according to the operation of the M’Naghten rules.

Griffin J applied the reasoning of Henchy J in People (A-G) v Hayes²⁸ and stated that

The [M’Naghten] rules do not take into account the capacity of a man on the basis of his knowledge to act or refrain from acting, and I believe it to be correct psychiatric science to accept that certain serious mental diseases, such as paranoia and schizophrenia, in certain cases enable a man to understand the morality or immorality of his act or the legality or illegality of it, or the nature and quality of it, but nevertheless prevent him from exercising a free volition as to whether he should or should not do that act.²⁹

Further, having understood the ‘capacity of a man to act or refrain from acting’ in terms of the ‘exercise of free volition’, Griffin J stated that:

If it is open to the jury to say that this man understood the nature and quality of his act, and understood its wrongfulness, morally and legally, but that nevertheless he was debarred from refraining from [acting] because of a defect of reason, due to his mental illness, it seems to me that it would be unjust, in the circumstances of this case not to allow the jury to consider the case on these grounds.³⁰

That is, an accused lacks ‘free volition’ where he or she is ‘debarred from refraining’ from acting in a particular fashion. Hence, an accused that cannot will not to do the act or cannot do otherwise is taken to lack free volition. The absence of a capacity to do otherwise will ground a defence of insanity where the reason for such absence is mental illness. Consequently, according to the judgment in Doyle, an accused may raise a defence of insanity, independent of a lack of knowledge as to the nature, quality or wrongness of his or her act, where he or she is ‘debarred from refraining from [acting] because of a defect of reason, due to his [or her] mental illness’.³¹ However, the judgment in Doyle fails to reveal how mental illness resulting in a defect of reason may debar an accused from refraining from acting and yet nevertheless allow him or her to know both the nature and quality of his or her act and understand its wrongness. The court merely points to ‘correct psychiatric’ evidence that will establish such mental malfunctioning.

In this respect it is interesting to note that Griffith J, stated, in obiter, that:

Having regard to the findings of the learned Circuit Court judge and the [psychiatric] evidence, it seems to me that the respondents have not made out a case that legal insanity absolved the youth, who set fire to the abattoir, from criminal responsibility.³²

While the issue of whether insanity has been established is a question of fact for a jury to consider, Griffith J’s remarks suggest that the facts did not reveal incapacity on the part of the accused to refrain from acting. In particular, the ability to make a choice for a reason and act on such a choice for that reason presupposes the ability to exercise control.³³ Consequently, the accused’s reason or motivation in burning down the abattoir as a means of protesting against the slaughter of the animals and his acting for that reason, would seem incongruent with the hypothesis that he was unable to exercise free volition.

It may be noted that to the extent to which the judgment in Doyle is reliant on psychiatric evidence it remains hostage to empirical evidence to the same degree as does the High Court approach in Sodeman and Brown. As noted above, the High Court cases of Sodeman³⁴ and A-G (SA) v Brown³⁵ make it clear that at common law, involuntary conduct arising from mental disorder may be used as evidence in establishing an accused’s incapacity to know the nature and wrongness of his or her act. The High Court ruling in these latter cases is of interest only on the assumption that volition and cognition track one another. That is, these judgments indicate that volitional defects are symptomatic of cognitive defects. Conversely, a case such as Doyle³⁶ endeavours to expand the common-law defence by recognizing a state of mental disorder characterized by involuntary conduct independent of a lack of knowledge of the nature, quality or wrongness on the part of the accused. That is, the Doyle approach is of interest to the extent to which an accused may experience involuntary conduct arising from mental disorder without any cognitive impairment. Hence, the Irish Supreme Court approach in Doyle is of interest only on the assumption that cognition may be separated from volition.

However, by adopting the safe-guard suggested above we are confronted by an important trade-off. The trade-off stems from the fact there is no objectively verifiable means of distinguishing an impulse which was not resisted from an impulse which was irresistible: distinguishing those accused who ‘could not’ from those who ‘would not’.³⁷ Consequently, by introducing an independent volitional limb we safeguard against the risk of punishing individuals who lack the capacity for voluntary conduct, yet, at the same time, a significant epistemic problem is raised regarding distinguishing those individuals who lack the capacity from those who choose not to exercise it. I will return to this issue when I come to consider various objections to the introduction of an independent volitional limb below.

The next section will outline the approach taken by the code jurisdictions in respect of involuntary conduct arising from mental disorder.

Code-jurisdiction approach

An instance of a code jurisdiction adopting an independent volitional limb is to be found in the Tasmanian Criminal Code.³⁸ Section 16(1)(b) of the Tasmanian Code stipulates that the defence of insanity may be raised by an individual where ‘the act or omission was done or made under an impulse which he or she was in substance deprived of any power to resist’. The Northern Territory Criminal Code³⁹ allows the defence to be raised by an accused that is ‘not able to control his or her actions’.⁴⁰ Similarly, the Australian Capital Territory (ACT) has included an independent volitional limb to its criminal code.⁴¹ The ACT Code stipulates that an accused may raise a defence of mental impairment where he or she ‘could not control [his or her] conduct’.⁴² In respect of the Queensland and Western Australian jurisdictions the M’Naghten rules were codified in section 27 of the Queensland and Western Australian Criminal Codes (Griffith Codes).⁴³ However, in contrast to the M’Naghten rules Griffith Code formulations of the insanity defence have recognized incapacity to control conduct as a separate basis for the insanity defence. An instance of a Griffith Code formulation adopting an independent volitional limb is to be found in section 27 of the Queensland Criminal Code:

(1) A person is not criminally responsible for an act or omission if at the time of doing the act or making the omission the person is in such state of mental disease or mental infirmity as to deprive the person of capacity to understand what the person is doing, or of capacity to control the person’s actions, or of capacity to know that the person ought not to do the act or make the omission.⁴⁴

Code jurisdictions, in keeping with the case at common law, hold that where an accused’s involuntariness is caused by a disease of the mind only the defence of non-responsibility is open.⁴⁵ Consequently, in such an instance an accused cannot maintain that he or she is entitled to an acquittal on the basis of involuntariness.⁴⁶

The Commonwealth Criminal Code defence of mental impairment is analogous to the Griffith Code formulations above:

7.3 Mental Impairment

(1) A person is not criminally responsible for an offence if, at the time of carrying out the conduct constituting the offence, the person was suffering from mental impairment that had the effect that:

(a) the person did not know the nature and quality of the conduct; or

(b) the person did not know that the conduct was wrong …; or

(c) the person was unable to control the conduct.⁴⁷

The Commonwealth Code preserves the Griffith Code position in respect of the degree of impairment an accused must suffer in relation to his or her capacity to control before the defence is raised. Under both the Griffith and Commonwealth Codes an accused must be ‘deprived of the capacity’, that is, be ‘unable to’, control his or her conduct in order for the defence to be established. By requiring a deprivation rather than an impairment of an accused’s capacity, the Griffith and Commonwealth Codes further restrict the operation of this limb of the defence.⁴⁸ However, in keeping with both the common law and the Griffith Code under the Commonwealth Code, an accused choosing to raise evidence of mental impairment in order to deny voluntariness must rely on the insanity defence.⁴⁹ Consequently, in such an instance an accused cannot maintain that he or she is entitled to an acquittal on the basis of involuntariness.⁵⁰

In contrast to the common-law formulation of the insanity defence, code-jurisdiction formulations of the defence provide a more expansive definition of insanity. In particular, code formulations allow an accused to raise a defence of insanity by showing that he or she has been deprived of the capacity to control his or her conduct as a result of mental impairment.⁵¹

Interpreting lack of capacity to control

Despite some differences in terminology, all code jurisdictions recognize a lack of capacity to control conduct as an independent ground of establishing the insanity defence. The absence of capacity for self-control may be interpreted in one of two ways.⁵² One interpretation views the absence of capacity for self-control as referring to those cases where the behaviour on the part of an accused is involuntary, that is, behaviour occurring independently of the exercise of the will.⁵³ This interpretation follows the High Court in R v Falconer,⁵⁴ where it was held that the requirement for voluntary conduct requires a person’s conscious mind to have directed the act because the notion of voluntariness or will requires the act to be made by the accused ‘“of [his or her] own free will and by decision” (per Kitto J in Vallance at 64) or by “the making of a choice to do” so (per Barwick CJ in Timbu Kolian at 53). The notion of “will” imports a consciousness in the actor of the nature of the act and the choice to do an act of that nature.’⁵⁵ On such an interpretation of the code jurisdiction’s limb the absence of a capacity to control is restricted to instances where an accused’s incapacity for self-control is interpreted merely as involuntary conduct.⁵⁶ That is, conduct of which the accused was not conscious. Consequently, an interpretation of the capacity to control as conduct occurring independently of the will would restrict the operation of the code’s second limb of the insanity defence to states of automatism. As expressed by Toohey J in Falconer:⁵⁷

Undoubtedly, automatism implies conduct which is involuntary. The use of descriptions such as ‘automatism’ should not obscure the fact that, in terms of the Code, where criminal responsibility is in issue, the question ultimately is whether the act or omission in respect of which an accused has been charged occurred independently of the exercise of his or her will. Automatism is merely a fact going to voluntariness: Hall (1988) 36 A Crim R 368 at 371.⁵⁸

However, by defining the incapacity to control limb of the defence narrowly as conduct which is merely involuntary, the volitional limb adopted by code jurisdictions would be rendered redundant as acts which are performed in a state of unconsciousness are also those acts in respect of which the accused did not know their nature and quality.⁵⁹

Another interpretation of an accused’s capacity to control seeks to cover instances of ‘irresistible impulse’ arising from a state of mental impairment.⁶⁰ The notion of irresistible impulse was considered in R v Moore,⁶¹ where it was held that:

This section [Criminal Code Act 1902 (WA) s 27] deals with the defence of insanity, and it shows in what cases persons who would otherwise be responsible for their acts are free from responsibility because they are insane. It treats as insane certain persons who under the old law would not have been treated as insane. It accepts the medical theory of uncontrollable impulse, and treats people who are insane to the extent that they have not the capacity to control their actions, whether from mental disease or natural mental infirmity, as being persons who are irresponsible.⁶²

A similar approach was adopted in the Western Australian case of Wray v R,⁶³ where the court upheld an appeal against conviction on the basis of medical evidence that the accused was suffering from dementia praecox which deprived him of the capacity to control his actions.

Interpreting an incapacity to control conduct in terms of an irresistible impulse, rather than merely as an instance of involuntary conduct due to mental disease, would provide a defence to those individuals who are deprived of the capacity to resist engaging in proscribed conduct and yet who may still know the nature and quality of their act. The introduction of a defence on the basis of an irresistible-impulse interpretation of capacity to control will be considered below.

Bronitt and McSherry have noted that, even in those jurisdictions where an independent volitional limb is available, claims of irresistible impulse are rarely used.⁶⁴ The authors suggest that the rarity of the use of the volitional component in these jurisdictions is explainable given that an accused’s lack of capacity to control must stem from a disease of the mind or a related concept. Yet, in those jurisdictions which do have an independent volitional limb, there is a reluctance to interpret a volitional disorder arising from, for example, an impulse-control disorder, as a disease of the mind for the purposes of the defence.

Moreover, as the authors remark, even where the issue has been raised, it has been relatively unsuccessful with only one reported case of an appeal against conviction succeeding.⁶⁵ Bronitt and McSherry hypothesize that such a relative lack of success may be attributable to the fact that the provision of an independent volitional limb ‘might be perceived as an “easy out” for persons who are seeking an excuse for yielding to temptation’.⁶⁶

The authors are correct in noting that not all states of mental disorder are necessarily acknowledged as diseases of the mind. However, this is due to the fact that the narrowness of psychiatric categorizations of mental disorder does not necessarily accord with the breadth of the expression disease of the mind and cognate terms as used at common law and in mental-health legislation.

Moreover, while determining the applicability of a diagnostic category to a condition suffered by a particular accused may accord with psychiatry’s therapeutic rationale, this is not always congruent with the law’s policy objectives. As a matter of policy, Ferguson points out, ‘the public expectation that citizens must in general take personal responsibility for their conduct is an important value which is essential to the continued preservation of peace and order in our society’.⁶⁷ So, for example, where the capacity for control is set too low there is a risk that such public expectation will be destroyed, and a disproportionate number of individuals will not be held to the relevant standard. Hence the fact that an independent volitional limb is rarely used in those jurisdictions where it is extant may in fact be due to policy considerations. That is, the reluctance on the part of judges to characterize a particular mental disorder as a disease of the mind may be attributable to extant policy considerations rather than a felt lack of need for the recognition of an independent volitional limb as such.

Further, it is sometimes argued that a reason why volitional disorders should not be allowed to ground the defence is because of the inherent difficulty of distinguishing an individual who chooses not to exercise his or her capacity to refrain from acting (’would not’) from an individual who lacks the capacity to refrain from acting (’could not’).⁶⁸ However, the difficulty of distinguishing an accused who has raised a bogus defence should not preclude the availability of an independent volitional limb to those who are deserving of the defence. Epistemic constraints, or what we may know of an accused’s intention, or motivation, are a recurring problem in the criminal law.⁶⁹ Several commentators have remarked on similar concerns arising in other areas of criminal law with respect to questions of degree, such as determining the requisite loss of control required for the partial defence of provocation or in dealing with legal concepts such as ‘knowledge’ and ‘negligence’.⁷⁰ The inherent difficulty of determining these issues in no way undermines the importance of such concepts to the criminal law. I will return to this issue in the context of pyromania below.

Moreover, an additional safeguard against bogus claims of involuntary conduct arising from mental disorder presents itself as a result of the degree of impairment required before a claim of involuntary conduct arising from the mental disorder will satisfy the defence. Given that the defence results in a finding of non-responsibility, it will be incumbent on the accused to satisfy the court to the requisite degree that his or her volitional impairment is sufficiently severe to warrant such a finding.⁷¹ In this respect it is noteworthy that both the Griffith and Commonwealth Codes require that an accused be ‘deprived’ of the capacity to control his or her conduct.⁷²

Another objection to the provision of an independent volitional limb is the claim that, as instances of volitional disorder amount to or involve a cognitive failure, the failure to provide an independent volitional limb will not necessarily deny an accused claiming incapacity to control his or her conduct a defence.⁷³ Bronitt and McSherry argue that, in keeping with modern psychological understanding, a person suffering from incapacity to control his or her conduct would not have his or her cognitive faculties unaffected.⁷⁴ On this account there can be no independent volitional disorder arising from a disease of the mind, as putative cases of exclusively volitional impairment will be found to involve cognitive failure. Loss of control tests wrongly

assume that a person can know what he or she is doing is wrong, yet be unable to control his or her actions. In reality, such tests assume that cognition remains completely unaffected, and this contradicts not only the holistic standpoint of modern psychology but also the view that the ability to reason plays an essential part in controlling conduct.⁷⁵

According to the above holistic model of mental functioning, a failure to provide an independent volitional limb will not result in injustice as an accused who claims incapacity to control his or her conduct will nevertheless still be able to raise a defence employing the current (cognitive) formulation of the M’Naghten rules.

However, there is no reason to doubt the existence of a serious mental disorder in certain cases precluding an individual from knowing the nature, quality and wrongness of his or her act while being prevented from exercising free volition in relation to such an act. While some mental disorders manifest a lack or impairment of cognitive capacity, this is not the case in all instances. I will argue in the next section that there are instances where a person suffering from some form of volitional disorder may have his or her capacity to conform to conduct severely restricted without any form of cognitive dysfunction. Consequently, there is no reason to doubt the existence of a serious mental disorder in certain cases precluding an individual from knowing the nature, quality and wrongness of his or her act while being prevented from exercising free volition in relation to such an act.

The next section will outline a category of psychiatric disorder characterized by volitional impairment without cognitive dysfunction, impulse-control disorder.

Impulse-control disorder: pyromania

This section will outline the characteristic features of the diagnostic category of impulse-control disorder. I will begin by remarking on the reasons why an individual who suffers from an impulse-control disorder should have the defence extended to him or her. This will be followed by an outline of the diagnostic features of one particular type of impulse-control disorder, pyromania, as they appear in two major classificatory manuals. However, before commencing with the above analysis certain remarks will be made in respect of the use of diagnostic manuals in forensic settings.