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Legal Insanity Standards: Their Structure and Elements

Part of the International Library of Ethics, Law, and the New Medicine book series (LIME,volume 71)


The variety of ways in which the moral notion that mental disorders may exculpate a defendant is reflected in criminal law, is impressive. In this chapter, several legal insanity standards are considered: the M’Naghten Rule, the irresistible impulse test, the Model Penal Code standard, the Durham Rule (also known as the product test), the Norwegian legal criterion, and insanity in the Netherlands.


  • Penal Code
  • Criminal Responsibility
  • Legal Standard
  • Common Morality
  • Commanding Voice

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  1. 1.

    Although I focus on some Western legal systems, the insanity defense is also available in other legal systems, see The insanity defense the world over by Simon and Ahn-Redding (2006).

  2. 2.

    The notion of common morality refers to what we share regarding moral rules and judgments. The term is used by Gert (2004, p. 8), who writes: “The existence of a common morality is supported by the widespread agreement on most moral matters by all moral agents.” It has also been adopted by Tom Beauchamp  (2003, p. 260): “I define the ‘common morality’ as the set of norms shared by all persons committed to the objectives of morality. The objectives of morality, I will argue, are those of promoting human flourishing by counteracting conditions that cause the quality of people’s lives to worsen.” Beauchamp and Childress (2009, p. 3) use the same concept, defining the notion as follows: “The common morality is the set of norms shared by all persons committed to morality.” The notion of a shared morality may also be phrased differently. For instance, Appelbaum was, as American Psychiatric Association President-elect, quoted as follows (Moran 2002, emphasis added): “‘It is clear that when juries are asked to consider the insanity defense, they are doing something much more than simply applying the legal standard that is handed to them,’ Appelbaum said. ‘They are making a moral judgment as to whether punishment is deserved. That’s a reasonable function, and I think it is precisely what we should ask our juries to do—to represent our morality at large.’” I will use the term a bit more loosely than Beauchamp and Childress, more in line with the Appelbaum quote.

  3. 3.

    See, e.g., Robinson (1996), p. 21 (in another translation). For Aristotle’s relevance to the insanity defense, see Sect. 4.1.

  4. 4.

    Cited from Plato (1980) 864D-E, see also Konstan (2013, p. 428). On mental illness in Plato, see, e.g., Sassi (2013).

  5. 5.

    In many legal systems, a specific type of impact of the disorder must be determined—for instance, influence on a defendant’s knowledge or behavioral control—before the defendant can be considered legally insane. Norway is an exception; Norwegian General Civil Penal Code § 44 merely states: “A person who was psychotic or unconscious at the time of committing the act shall not be liable to a penalty. The same applies to a person who at the time of committing the act was mentally retarded to a high degree.” Quote taken from the English translation of the Breivik verdict, Lovdata TOSLO-2011-188627-24E.

  6. 6.

    In this book, I cite a number of legal cases, some historical, some of recent date. The presentation and interpretation of these cases is based on generally accessible information, highlighting certain interesting aspects (often as an illustration), and should never be interpreted as “expert opinion” on the case or the defendant. I was not involved in any of the cases.

  7. 7.

    Morse (2011b, p. 894), yet, differences between jurisdictions exist.

  8. 8.

    DSM-5 (American Psychiatric Association 2013): “However, the use of DSM-5 should be informed by an awareness of the risks and limitations of its use in forensic settings. When DSM-5 categories, criteria, and textual descriptions are employed for forensic purposes, there is a risk that diagnostic information will be misused or misunderstood. These dangers arise because of the imperfect fit between the questions of ultimate concern to the law and the information contained in a clinical diagnosis. In most situations, the clinical diagnosis of a DSM-5 mental disorder such as intellectual disability (intellectual developmental disorder), schizophrenia, major neurocognitive disorder, gambling disorder, or pedophilic disorder does not imply that an individual with such a condition meets legal criteria for the presence of a mental disorder or a specified legal standard (e.g., for competence, criminal responsibility, or disability). For the latter, additional information is usually required beyond that contained in the DSM-5 diagnosis, which might include information about the individual’s functional impairments and how these impairments affect the particular abilities in question.” See also DSM-5, ‘Definition of a mental disorder’: “Additional information is usually required beyond that contained in the DSM-5 diagnostic criteria in order to make legal judgments on such issues as criminal responsibility, eligibility for disability compensation, and competency (see ‘Cautionary Statement for Forensic Use of DSM-5’ elsewhere in this manual).”

  9. 9.

    It is also possible that expert testimony about a certain disorder will not meet the standard for admissibility of evidence, see, e.g., on Posttraumatic Stress Disorder: Appelbaum et al. (1993), Berger et al. (2012).

  10. 10.

    Court of Appeals Arnhem, 18 May 2011, ECLI:NL:GHARN:2011:BQ4981.

  11. 11.

    Quote from Moran (1981, p. 1).

  12. 12.

    See Robinson (1996), Simon and Ahn-Redding (2006).

  13. 13.

    On this famous case, see Moran (1981). Moran also investigated the correct spelling of the name, concluding that it should be McNaughtan. I will continue to use the usual spelling of the name in the legal standard.

  14. 14.

    M’Naghten’s Case, 10 Cl. & Fin. 200, 8 Eng. Rep. 718 (H.L. 1843).

  15. 15.

    Yet, it could be argued that this is not ‘real’ psychopathology, because it is a legal, not a clinical definition (see also Chap. 7 on the element of mental disorder in the insanity test).

  16. 16.

    In Kemp , the meaning of defect of reason was clarified in English law. Lord Devlin stated: “A defect of reason is by itself enough to make the act irrational and therefore normally to exclude responsibility in law. But the Rule was not intended to apply to defects of reason caused simply by brutish stupidity without rational power.” R v Kemp [1957] QB 399.

  17. 17.

    As Yaffe puts it (2013, p. 352): “Numerous difficult, perhaps intractable, questions exist concerning what, exactly, a defendant’s disorder must do to his psychology if he is to meet this legal definition of insanity. For instance: Which features of one’s conduct are included in its ‘nature and quality’? For example, does a defendant who thinks he’s wielding a knife when he is actually wielding a broken bottle know the ‘nature and quality’ of his act? Or does a defendant who knows that his act is illegal but falsely believes it is morally obligatory, or at least morally permissible, know that ‘he is doing what is wrong’? What if he knows it is morally wrong but falsely believes it is legal, perhaps because he deludes himself to be an agent of the government who is licensed to commit crimes? And so on.”

  18. 18.

    Levy writes: “I shall argue that psychopaths do not possess the relevant moral knowledge for distinctively moral responsibility; lacking this knowledge, they are unable to control their actions in the light of moral reasons. This conclusion is of obvious practical significance.” (Levy 2007, p. 128). See Vargas and Nichols (2007) for a response to Levy’s argument.

  19. 19.

    It is of interest that under English law, as interpreted in R v. Codere [1916] 12 Cr App R 21 (CA), Lord Reading C.J. stated (Friedland 1978, p. 613): “It is said that ‘quality’ is to be regarded as characterising the moral, as contrasted with the physical, aspects of the deed. The court cannot agree with that view of the meaning of the words ‘nature and quality.’ The court is of the opinion that in using the language ‘nature and quality’ the judges were only dealing with the physical character of the act and were not intending to distinguish between the physical and moral aspects of the act.” According to Loughnan (2012, p. 121), in Codere, wrong was understood as moral wrongness, “However, since that decision, the courts have moved to a narrower interpretation of ‘wrongness’ that equates it with ‘legal wrong.’”

  20. 20.

    Mackay (1995, p. 86) argues that causality has been tested in the “sense that the M’Naghten Rules have been interpreted to require a causal relation between the accused’s ‘defect of reason’ and his ‘disease of the mind.’”

  21. 21.

    A case in the Netherlands, Court of Appeals Amsterdam, 17 September 2010, ECLI:NL:GHAMS:2010:BN7345.

  22. 22.

    See also the case of Andrea Yates , who “on June 20, 2001, in less than an hour…drowned all of her [five] children in the bathtub, one by one.” (Denno 2003). In fact, “According to Andrea, she killed her children to save them from Satan and her own evil maternal influences…” (Denno 2003).

  23. 23.

    Sinnott-Armstrong and Levy (2011) distinguish between four interpretations of wrongness: legal wrongfulness on the one hand and three senses of moral wrongfulness on the other: personal, social, and—as Sinnott-Armstrong and Levy call it—“plain morally wrong.” These three variants of moral wrongfulness are explained as follows (2011, pp. 302-303): “The second possibility [socially wrong] is that a responsible agent needs to know that the act is contrary to the moral beliefs of most people in the particular society—that is, socially wrong. To call an act socially wrong in this sense is to refer not merely to custom or etiquette but, instead, to moral beliefs and principles generally accepted in that community. In order for a defendant to know that an act is socially wrong, then, she must know something about what people in a given society generally believe about morality. A third possibility is that a responsible agent needs to know that the act violates that particular agent’s own moral principles or moral beliefs—that is, that it is personally wrong. In order for a defendant to know what is personally wrong, she must be aware of her own moral beliefs and how to apply them. Finally, a responsible agent might need to know that the act is just plain morally wrong. For a defendant to know this is not for the defendant to know what other people do or would say or believe about the act or about its moral status. Instead, it is to know something about the act itself—namely, that there is at least one property of the act that gives it the moral status of being wrong.” Although Sinnott-Armstrong and Levy refer to these three notions as “social, personal, and moral” wrongness, they all involve moral notions. Therefore, I consider them three senses of the moral explanation of wrongness in M’Naghten (see also Sinnott-Armstrong and Levy 2011, p. 313, and note 53 for support for this view).

  24. 24.

    Sinnott-Armstrong and Levy (2011, pp. 303–304, references omitted) write: “M’Naghten jurisdictions do not agree about which kind of wrongness must be known in order for an agent to be responsible. Most seem to have remained silent, and at least two have explicitly refrained from adopting a position, on this issue. Regarding the jurisdictions that have taken a position, some of them maintain that defendants may generally be found not guilty by reason of insanity only if, as a result of mental illness, they did not know that their acts were legally wrong. Other jurisdictions explicitly specify that legal knowledge is not enough for responsibility; that even if defendants knew that their acts were illegal, they might still be eligible for a verdict of not guilty by reason of insanity if they did not know that their acts were socially wrong. No jurisdiction seems to accept the view that a defendant may be found not guilty by reason of insanity simply because he failed to know that his act violated his own personal moral beliefs.” On the issue of wrongness, see also Lord Goddard CJ who stated in Windle : “it would be an unfortunate thing if it were left to juries to decide whether some particular act was morally right or wrong. The test must be whether it was contrary to the law…” R v Windle [1952] 2 QB 826.

  25. 25.

    See, on such command hallucinations that cannot be disobeyed Braham et al. (2004); Bucci et al. (2013).

  26. 26.

    R. Jay Wallace (1994, p. 170) writes: “Almost from the time of their first formulation, the M’Naghten Rules have come under fire for their exclusive focus on cognitive defects or defects of reason in mental illness and insanity. It has been argued that mental illness may equally cause defects of the will, such as susceptibility to irresistible impulses…”

  27. 27.

    As Wallace (1994, p. 168) rightfully notes, “cases in which a mentally ill person literally has no idea about the nature and quality of her acts seem quite rare. More commonly, when someone in the grip of such conditions as depression or paranoia does something wrong (attacking a relative, say), she will know perfectly well that she is attacking the person; indeed, such actions are sometimes elaborately premeditated. But there will often be present a ‘defect of reason’ that prevents the agent from accurately assessing the moral quality of her act.”

  28. 28.

    While I use the term “context,” Wallace (1994, p. 169) uses the term “situation”: “One must also be able to attain a clear and accurate view of the morally relevant features of the situation in which one is acting, and this is something that a delusion would appear to preclude.”

  29. 29.

    Note that M’Naghten does not require the defendant to believe that his or her action was “good,” “justified,” or “praiseworthy.” It merely requires that the wrongfulness of the action was not known to the defendant due to a mental disorder’s impact on that defendant’s reason.

  30. 30.

    Slobogin (2003, p. 317–18) writes about M’Naghten: “A third part of the House of Lords’ opinion is not as well known. Toward the end of the M’Naghten opinion the Lords announced a special test for cases of ‘partial delusion,’ or what today might be called an encapsulated delusion. According to the Lords, individuals with partial delusions should be placed ‘in the same situation as to responsibility as if the fact with respect to which the delusion exists were real.’” Cf. Simon and Ahn-Redding (2006, p. 201) refer to the insanity defense in Nigeria (Section 28 of the Nigerian Criminal Code Act 1990) as follows: “A person whose mind, at the time of his doing or omitting to do an act, is affected by delusions on some specific matter or matters, but who is not otherwise entitled to the benefit of the foregoing provisions of this section, is criminally responsible for the act or omission to the same extent as if the real state of things had been such as he was introduced by the delusions to believe to exist.” What is actually stated here is that the defendant’s actions should be judged based on the assumption that the delusional beliefs were true. See also Bortolotti et al. (2014, p. 380) who emphasize that not all delusions that help explain certain criminal behaviour provide an excuse: “In this respect, we want to draw a parallel with the case of a young man with a diagnosis of schizophrenia who attacked his neighbor after experiencing auditory hallucinations about the neighbor making loud noise and insulting him repeatedly.” Bortolotti et al. (2014, pp. 380–381) elaborate on the case as follows, based on an earlier publication: “[S]uppose Bill had actually had a very noisy neighbor. What kind of ascription of responsibility would we have made in relation to the harm inflicted on his neighbor in those circumstances? What kind of punishment would Bill have deserved for his attacking his truly noisy neighbor? Should the fact that the experiences were hallucinatory (and thereby that the neighbor was not in fact noisy) make a difference in relation to how we conceive of Bill’s responsibility for what he did and of the punishment he deserves? It is true that Bill was hallucinating: He was hallucinating that his neighbor was making loud noises, and the content of the hallucination explains in part why he attacked his neighbor. Had he not hallucinated that his neighbor was making loud noises, Bill would have probably not attacked and harmed his neighbor. But it is also true that having noisy neighbors does not morally justify assaulting them. That is, had Bill’s neighbor been truly noisy, Bill would have still been doing something blameable in assaulting his neighbor. If one has a noisy neighbor, then one should try to convince his neighbor to be less noisy, and, failing that, one should perhaps call the police.” They interpret the case as follows: “Here, what we find is that the psychotic symptoms experienced by Bill help explain his aggressive behaviour towards his neighbour, although they are not sufficient to motivate his actions.” In fact, what Bortolotti et al. have done is assume the truth of Bill’s psychotic belief and then evaluate Bill’s actions based on that assumption, concluding that what Bill did is still blameworthy, even though the symptoms help explain why he acted as he did. Meanwhile, in some cases it may be difficult to assume the truth of a delusion and its possible consequences. For instance, if another person were an alien in disguise, what would be a permissible range actions? Or, assuming the existence of a demon, what should or shouldn’t we do? Certain delusions may even defy the laws of physics—how can we assume their truth and then reason about what is and is not permissible in a world in which our laws of physics no longer apply?

  31. 31.

    However, see the next chapter, in which it becomes clear that some do not trust the reliability of psychiatric evaluations.

  32. 32.

    Still, some people may feel that commanding voices as described in the second case should not lead to exculpation by reason of insanity, for instance, because they may be faked. Then, the fact that the influence of this psychopathological phenomenon is not covered by M’Naghten does not constitute a weakness of the standard, but rather the contrary. On faking command hallucinations, see McCarthy-Jones and Resnick (2014), Resnick and Knoll (2005). We will return to issue of faking in the next chapter.

  33. 33.

    New Mexico Supreme Court, State v. White, 58 N.M. 324, 270 P.2d 727, 730 (1954).

  34. 34.

    Moore (1984) adds: “There are thus basically two kinds of traditional insanity tests: those based on the ignorance of the mentally ill accused person; and those based on some notion of his being compelled to act as he did.”

  35. 35.

    Hart (2008, pp. 189–90) notes: “Angrily and enviously, many of the critics [of M’Naghten] pointed to foreign legal systems which were free of the English obsession with this single element of knowledge as the sole constituent of responsibility. As far back as 1810 the French Code simply excused those suffering from madness (démence) without specifying any particular connexion between this and the particular act done. The German Code of 1871 spoke of inability or impaired ability to recognize the wrongness of conduct or to act in accordance with this recognition. It thus, correctly, according to the critics, treated as crucial to the issue of responsibility not knowledge but the capacity to conform to law. The Belgian Loi de Défence Sociale of 1930 makes no reference to knowledge or intelligence but speaks simply of a person’s lack of ability as a consequence of mental abnormality to control his action.”

  36. 36.

    See also Morse (2011b, p. 893, references omitted): “Lack of control is not well understood conceptually or scientifically in any of the relevant disciplines such as philosophy, psychology, and psychiatry, however, and we lack operationalized tests to accurately identify this type of lack of capacity. I have long been a critic of such standards for just these reasons. The American Bar Association and the American Psychiatric Association also urged the rejection of control tests for legal insanity on these grounds. I suggest that for all cases in which a control test may seem required, the reason can be better characterized as a rationality defect because control difficulties flow from lack of access to the good reasons not to act in the wrong way.” In the “Cautionary Statement for Forensic Use of DSM-5” we can read about control over one’s behavior: “Nonclinical decision makers should also be cautioned that a diagnosis does not carry any necessary implications regarding the etiology or causes of the individual’s mental disorder or the individual’s degree of control over behaviors that may be associated with the disorder. Even when diminished control over one’s behavior is a feature of the disorder, having the diagnosis in itself does not demonstrate that a particular individual is (or was) unable to control his or her behavior at a particular time.”

  37. 37.

    See also Morse (2000, p. 264, footnote omitted): “I am not sure what it means to be unable to control oneself, but if this condition warrants preventive detention, it should also furnish an excuse to crime. After all, could it possibly be fair to blame and to punish those who genuinely cannot control themselves?”

  38. 38.

    Fingarette (2004, p. 70): “First of all, the notion of irresistible impulse is for theoretical purposes a very troublesome notion. The problem has been well expressed in the question: How do we tell the difference between ‘He could not resist his impulse’ and ‘He did not resist his impulse’? This becomes in practice a very perplexing issue in the law. Typically, when it comes up openly, as in insanity cases, for example, it involves psychiatric testimony. Yet there is no theoretical understanding of how to apply the distinction.”

  39. 39.

    Insanity Defense Work Group, American Psychiatric Association (“American Psychiatric Association statement on the insanity defense,” 1983, p. 685), also cited by Elliot (1996, p.14). See, e.g., Glannon (2011) on the problems of the notion of impulse control in mental disorder.

  40. 40.

    References omitted. Penney (2012, p. 101) also writes here: “Even with the assistance of expert testimony, the argument runs, it is simply too difficult for judges and juries to distinguish between the capable and the incapable. … Indeed, it was primarily this concern that led both the American Psychiatric Association (1983) and the American Bar Association (1989) to advocate for the removal of the control test in the aftermath of the Hinckley case.”

  41. 41.

    Model Penal Code (American Law Institute 1985).

  42. 42.

    See Packer (2009), Appendix A.

  43. 43.

    See Sinnott-Armstrong and Levy (2011, p. 314): “The change from ‘know’ in the M’Naghten rule to ‘appreciate’ in the MPC [Model Penal Code] rule is arguably an attempt to move beyond a purely abstract account of knowledge. Appreciation requires the person not only to know the right answers to questions but also to understand those answers.” See also Mackay (1990) on “appreciate” in the Canadian standard for legal insanity, which is otherwise very similar to M’Naghten.

  44. 44.

    The Explanatory Note, Model Penal Code §4 (American Law Institute) reads: “An individual’s failure to appreciate the criminality of his conduct may consist in a lack of awareness of what he is doing or a misapprehension of material circumstances, or a failure to apprehend the significance of his actions in some deeper sense. Wrongfulness is suggested as a possible alternative to criminality, though it is recognized that few cases are likely to arise in which the variation will be determinative.”

  45. 45.

    According to Becker (2003, p. 44), “The ALI [American Law Institute] test was viewed as a broader more expansive test of insanity as compared to the outdated M’Naghten test… The ALI test also broadened the insanity test to include a volitional or ‘irresistible impulse’ component. The test focused on the ‘defendant’s understanding of his conduct’ and also on the ‘defendant’s ability to control his actions.’”

  46. 46.

    Cf. Hart (2008, p. 189): “From the start English critics denounced these [M’Naghten] rules because their effect is to excuse from criminal responsibility only those whose mental abnormality resulted in lack of knowledge: in the eyes of these critics this amounted to a dogmatic refusal to acknowledge the fact that a man might know what he was doing and that it was wrong or illegal and yet because of his abnormal mental state might lack the capacity to control his action. This lack of capacity, the critics urged, must be the fundamental point in any intelligible doctrine of responsibility. The point just is that in a civilized system only those who could have kept the law should be punished. Why else should we bother about a man’s knowledge or intention or other mental element except as throwing light on this?”

  47. 47.

    Not all psychopaths, though, fulfil the criteria of antisocial personality disorder.

  48. 48.

    References omitted.

  49. 49.

    Penney (2012, p. 101) writes that it is not “evident that impulsivity is so clinically nebulous that courts cannot determine claims with reasonable reliability.”

  50. 50.

    Penney (2012, p. 101, references omitted).

  51. 51.

    See Redding (2006, pp. 89–90, references omitted) on those who oppose a control prong: “Opponents of control tests have offered, and continue to offer, three rationales for their abandonment: (1) that cognitive tests for insanity are sufficient, since those with impaired impulse control will also be cognitively impaired; (2) that mental health professionals are incapable of reliably assessing the capacity for impulse control, particularly in relation to criminal behavior, or of differentiating between a truly irresistible impulse and an impulse that is merely difficult to resist; and, therefore, that control tests lead to erroneous insanity acquittals; and (3) that because ‘they directly pose the question of whether a person could control his or her behavior,’ control tests run counter to the law’s assumption of free will and notion that criminals should be held accountable for their crimes.” Adding to that: “As I demonstrate below, current neuroscience and clinical research challenges each of these claims.”

  52. 52.

    Penney (2012, p. 101, references omitted).

  53. 53.

    Morse (2000, p. 257, emphasis added) writes: “I am firmly of the opinion that disorders of desire should excuse only in those cases in which the desire is so strong and overwhelming that the agent at least temporarily loses the capacity to be guided by reason. Thus, the problem would be irrationality and not compulsion.”

  54. 54.

    See also Morse (2002, p. 1065): “Indeed, as I argue below, if one examines closely most cases of alleged ‘loss of control,’ they essentially raise claims that, for some reason, the agent could not ‘think straight’ or bring reason to bear under the circumstances.” Others, like Penney (2012) and Redding (2006), disagree with Morse on this issue.

  55. 55.

    Morse (2002, p. 1041) writes: “The criteria for the dominant, ‘cognitive’ insanity defense tests include a mental abnormality that causes a further, necessary defect in rationality. For example, the M’Naghten test requires that the mental abnormality cause the person not to know the nature and quality of the act or not to know that it was wrong. The cognitive criteria of the American Law Institute’s Model Penal Code test require mental abnormality to produce a lack of substantial capacity to appreciate the criminality or wrongfulness of one’s act.”

  56. 56.

    In fact, rationally controlling one’s behavior may well be considered to be a cognitive capacity. For example, the domain in neuroscience that studies such behavioral control—in health and disease—is often called “cognitive neuroscience.” See, e.g., Astle and Scerif (2009).

  57. 57.

    See also Chap. 4 on irrationality.

  58. 58.

    Penney (2012, p. 101). I assume that Penney has in mind an inability to exert control regarding the criminal act and that “total” does not refer to all aspects of human functioning (such as, e.g., bladder control, see Chap. 6).

  59. 59.

    See Sinnott-Armstrong and Levy (2011, p. 324): “…shifting the burden to the defense might increase the chance of punishing people who are not guilty, if insane people really are not guilty.” See also the next chapter on arguments against the insanity defense.

  60. 60.

    An extensive overview of legal insanity in U.S. jurisdictions can also be found in Janofsky et al. (2014). Note that differences regarding legal insanity across jurisdictions are not limited to the United States. For instance, Ferris (2010, p. 364–365) writes about Australia : “Although Australian states may apparently have given some support to this attempt at harmonization of the law, in practice the Model Code has been modified and applied in disparate ways. For example, South Australia has not included severe personality disorder as a condition capable of producing mental impairment (…). Victoria has not included the volitional element concerning control of conduct in its mental impairment legislation (…). New South Wales has ignored the Model Code altogether…”

  61. 61.

    Helm et al. (2016) performed a “mock juror” study among 477 undergraduate students (who participated in the study for course credit) comparing M’Naghten to the Model Penal Code criteria. Their results appear to downplay the relevance of the differences between jurisdictions as far as the test for insanity is concerned: “The results of this study support the contention that jurors’ decisions in insanity cases are not affected by whether they are asked to decide based on the Model Penal Code test (with a rationality limb and a control limb) or on the McNaughten test (based entirely on rationality), even when considering a defendant suffering from a clear control disorder. This suggests that jurors are making decisions based on who they think is insane rather than on the specific legal standard they are given and is consistent with existing literature showing that jurors tend to use their own conceptions of insanity rather than legal definitions when making determinations.” Yet, even if this is true for jurors, the extent to which it is true for judges is unclear.

  62. 62.

    Durham v. United States, 214 F. 2d 862 (D.C. Cir., 1954).

  63. 63.

    See Packer (2009, Appendix A).

  64. 64.

    Gerber (1975, p. 124). He also writes on that page: “Before 1954 the District of Columbia employed the right-wrong rule of M’Naghten taken together with the irresistible impulse test. Two principal problems arose in attempting to apply this standard. First, the antiquated terminology of M’Naghten ceased to represent society’s notion of who should be punished relative to the existing state of psychiatric knowledge. Second, expert witnesses felt obliged to go outside their expertise into the realm of law and social morality in testifying as to whether defendants knew right from wrong. The issue of responsibility was framed so narrowly that experts felt precluded from adequately describing the ramifications and manifestations of a defendant’s illness relevant to an assessment of criminal responsibility.” In Durham, the court concluded that “a broader test” than M’Naghten had to be adopted.

  65. 65.

    The term “mental disease or defect” in this standard has also been criticized, but I will focus on the product component, since that is the distinguishing feature of the Durham test.

  66. 66.

    Note that, in Blocker, Judge Burger also recognized that “Of course legal rules should be flexible enough to embrace the bona fide, and scientifically recognized developments and discoveries of medicine.”

  67. 67.

    Translation taken from Syse (2014), which is identical to the English translation of the Breivik verdict Lovdata TOSLO-2011-188627-24E. Since the section does not mention the terms “responsibility”, “liability” or a related concept, it is not completely clear to me that it concerns insanity. Still, since it is considered to concern insanity, I will refer to it as an insanity standard.

  68. 68.

    Taken also from Lovdata TOSLO-2011-188627-24E, see also Syse (2014).

  69. 69.

    Unconsciousness is added, but this probably refers to highly exceptional cases. Committing crimes and being unconscious is a rare combination.

  70. 70.

    See also Packer (2009, p. 30) on the U.S. context, “most successful insanity defenses involve a psychotic disorder.”

  71. 71.

    See, e.g., Janofsky et al. (2014, S29) on the types of disorders that may be accepted for insanity defenses in the U.S. context: “There are clear trends in the courts’ acceptance of some diagnosable mental disorders and syndromes. Psychotic disorders, such as schizophrenia, schizoaffective disorder, and mood disorders with psychotic features are diagnoses that typically qualify as serious or severe mental disorders or mental disease. Other diagnoses differ in outcome, depending on the facts of the case, the degree and nature of the symptoms, and the jurisdictional precedent. For example, personality disorders, paraphilias, impulse-control disorders, dissociative identity disorders , and developmental disorders can vary widely in terms of acceptance. Certain cognitive disorders, such as dementia or delirium, may also qualify as mental disease or defect, depending on circumstances and jurisdiction.”

  72. 72.

    On Post-traumatic stress disorder (PTSD), see Appelbaum et al. (1993), Berger et al. (2012), Packer (2009). As Berger et al. (2012, p. 512) write, “Shortly after its introduction into DSM-III in 1980, PTSD itself became the basis for successful insanity defenses. In State of New Jersey v. Cocuzza, the defendant, a Vietnam veteran who assaulted a police officer was found to be not guilty by reason of insanity. Mr. Cocuzza maintained that he believed he was attacking enemy soldiers, and his claim was supported by the testimony of a police officer that Mr. Cocuzza was holding a stick as if it were a rifle.”

  73. 73.

    Syse (2014, p. 405). For criticism regarding the Norwegian criterion for insanity, see also Bortolotti et al. (2014).

  74. 74.

    See also Penney (2012).

  75. 75.

    Tak (2008). This situation is different from that in Sweden, where the insanity defense has been abolished. It is available in the Netherlands, but no specific criteria for legal insanity have been formulated to guide courts in ascertaining a defendant’s insanity, see also Meynen (2013b), Radovic et al. (2015).

  76. 76.

    Section 39 of the Dutch Criminal Code, translation from The American Series of Foreign Penal Codes (Netherlands 1997, p. 73).

  77. 77.

    Partially adapted from Van Kordelaar (2002). There are other questions about the risk of recidivism and possible ways to reduce that risk, but these have been omitted here. As of September 2016, the Netherlands Institute of Forensic Psychiatry and Psychology (NIFP) will use an adjusted format of three degrees of criminal responsibility.

  78. 78.

    In the Netherlands, there are five degrees of legal responsibility: responsible, slightly diminished responsibility, diminished responsibility, strongly diminished responsibility, insanity—see also the introductory chapter.

  79. 79.

    Cited and translated: District Court Haarlem, 2 February 2006, ECLI:NL:RBHAA:2006:AV0882.

  80. 80.

    Cited and translated: District Court Utrecht, 19 October 2011, ECLI:NL:RBUTR:2011:BT8735.

  81. 81.

    When evaluating Dutch legal and forensic practice, case law must also be taken into account.

  82. 82.

    Beukers (2005), Hummelen and Aben (2015), Meynen and Kooijmans (2015).

  83. 83.

    Buchanan (2006, p. 19) mentions a “longstanding and widespread concern that psychiatric testimony is more likely than other evidence to intrude into the jury’s realm.”

  84. 84.

    Janofsky et al. (2014, emphasis added), see also Knoll and Resnick (2008) on the United States context. The 2014 AAPL Guideline reads, more specifically: “The forensic psychiatrist performing an insanity defense evaluation must answer three basic questions:

    1. 1.

      Did the defendant suffer from a mental disorder at the time of the alleged crime? (retrospective mental state evaluation)

    2. 2.

      Was there a relationship between the mental disorder and the criminal behavior?

    3. 3.

      If so, were the criteria met for the jurisdiction’s legal test for being found not criminally responsible?”

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Meynen, G. (2016). Legal Insanity Standards: Their Structure and Elements. In: Legal Insanity: Explorations in Psychiatry, Law, and Ethics. International Library of Ethics, Law, and the New Medicine, vol 71. Springer, Cham.

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