Psychopaths and Insanity: Law, Ethics, Cognitive Neuroscience and Criminal Responsibility
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Psychopaths and insanity: Law, ethics, cognitive neuroscience and criminal responsibility A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy (PhD) in the Faculty of Humanities 2014 Simon D Barnes School of Law Contents List of Tables 5 List of Figures 6 Abstract 7 Declaration 8 Copyright statement 9 Introduction 10 0.1 Background ................................. 10 0.2 Contribution ................................. 12 0.3 Implications of contribution ......................... 13 0.4 Legal focus ................................. 14 0.5 Methodology and sources .......................... 15 0.6 Overview .................................. 15 1 Psychopaths and the current insanity defence in English law 18 1.1 Introduction ................................. 18 1.2 The M’Naghten Rules, and historical context . 19 1.3 Initial analysis of Rule 3 ........................... 21 1.3.1 ‘defect of reason’ .......................... 21 1.3.2 ‘from disease of the mind’ ..................... 23 1.3.3 Limb 1: lack of knowledge of the ‘nature and quality’ of the act . 30 1.3.4 Limb 2: lack of knowledge of the wrongfulness of the act . 32 2 2 What is psychopathy? 37 2.1 Introduction ................................. 37 2.2 A brief historical perspective on psychopathy: from Pinel to Cleckley . 38 2.3 Psychopathy checklist-revised (PCL-R) ................... 44 2.4 Is psychopathy a morally evaluative concept? . 50 2.5 Is psychopathy a mental illness? ....................... 56 2.5.1 Introduction and scope ....................... 56 2.5.2 Why Antisocial personality disorder in DSM-IV/5 is not a good candidate .............................. 58 2.5.3 PCL-R psychopathy as a candidate mental disorder . 64 3 The prima facie case for access to an insanity defence 75 3.1 Introduction ................................. 75 3.2 Psychopaths, social practices and ‘reasons-responsiveness’ compatibilism . 77 3.2.1 Hume and Peter Strawson ...................... 77 3.2.2 Wallace’s account .......................... 81 3.2.3 Fischer and Ravizza’s theory .................... 86 3.2.4 Responding to the ‘Basic Argument’ . 90 3.2.5 Reasons-responsiveness versus ‘mesh’ compatibilism . 92 3.3 A note on neurobiological causes ...................... 96 3.4 Moral competence, moral responsibility and criminal responsibility . 100 3.5 The prima facie case and ‘knowledge’ in the M’Naghten Rules . 109 4 Psychopaths and the moral/conventional distinction 113 4.1 Introduction .................................113 4.2 What is a moral judgment? .........................114 4.3 The moral/conventional distinction test ...................115 4.4 Blair et al.’s research, and a more recent study . 119 4.5 Summary ..................................123 3 5 Relevant psychopaths and relevant criminal offences 124 5.1 Introduction .................................124 5.2 Which psychopaths? .............................125 5.2.1 Introduction: behind Cleckley’s mask . 125 5.2.2 Identifying relevant brain areas and circuits . 129 5.2.2.1 Psychopaths and moral dilemmas . 130 5.2.2.2 Moral verdicts versus brain activity . 132 5.2.2.3 Wider abnormalities . 134 5.2.3 Identifying relevant genes . 138 5.2.4 Understanding the epigenetic control of relevant genes . 142 5.2.5 Developing biomarkers . 146 5.2.6 ‘Relevant psychopaths’ . 149 5.3 Which criminal offences? . 152 6 Relevant psychopaths, access to an insanity defence and wider issues 157 6.1 Introduction .................................157 6.2 Current law and policy, and the consequences of a finding of NGRI . 159 6.3 Should an insanity defence be made available to relevant psychopaths? . 168 6.3.1 Exculpation, mitigation and risk . 168 6.3.2 Limitations of analysis, and conclusion . 175 Conclusion 179 References 188 Primary legal sources ...............................188 Cases ....................................188 Legislation ..................................189 Other references ..................................191 Word count: 73,592 4 List of Tables 2.1 Cleckley’s 16 diagnostic criteria for psychopathy . 42 2.2 PCL-R factors, facets and items ......................... 45 2.3 Diagnostic criteria for DSM-IV-TR antisocial personality disorder . 60 5 List of Figures 5.1 Lykken’s relationship between genotype, socialisation and parental competence 144 6 Abstract University of Manchester Simon Dennis Barnes Doctor of Philosophy (PhD) Psychopaths and insanity: Law, ethics, cognitive neuroscience and criminal responsibility 2014 In many jurisdictions, including England and Wales, psychopaths are unable to succeed with an insanity defence. This has been influenced by a legal view of psychopathy as a condition characterised by a reduced ability to comply with the law, which is otherwise fully understood. Evidence from cognitive neuroscience, however, may potentially challenge this traditional legal conception of psychopathy. In this regard it has already been suggested, based partly on scientific evidence, that it may be appropriate for at least some psychopaths to succeed with an insanity defence where they can be shown to lack moral competence. In this thesis, I critically examine this possibility. I first examine the insanity defence in English law, showing how psychopaths have effectively been excluded from the defence by judicial interpretation of the insanity defence criteria. Consequently, if psychopaths lacking moral competence were to be identified, reform (or reinterpretation) of the defence would be required. I then present philosophical arguments in favour of the case that some psy- chopaths should gain access to an insanity defence, before clarifying which psychopaths ought potentially to succeed, and which criminal offences ought potentially to be relevant, for the purposes of a reformed or reinterpreted defence. In order to clarify which psychopaths are relevant psychopaths (RPs), it is necessary to go beyond existing scientific evidence. It is argued, based on emerging neuroscientific find- ings and current research techniques, that while it is not currently possible to identify RPs, it may be possible in the future. Even if it this becomes possible, however, the philosophical case for access to an insanity defence remains deeply problematic. Although RPs may lack moral competence, for example, they may nevertheless possess other capacities relevant to criminal responsibility. After closer examination, it is argued that the case for access to an insanity defence may be best viewed as a case for mitigation rather than exculpation. I conclude by considering some of the implications of this analysis in an English legal context, should it become possible to identify RPs. Of particular relevance is the possibility that RPs may be at high risk of causing serious harm to others. This illuminates important possible relationships between responsibility and risk, and diagnostic advancements and risk assessment, in this area. There are also broader implications for the management of psychopaths in the future, given that greater scientific understanding may lead to enhanced predictive abilities that could tempt policymakers towards more radical strategies. This thesis contributes to an ongoing debate about the role that cognitive neuroscience may play in decisions about the criminal responsibility of psychopaths. My main contribu- tion is to clarify how psychopaths lacking moral competence may be identified in the future, and relate this neuroscientific discourse to arguments for providing these persons with ac- cess to an insanity defence. It is argued, however, by reference to legal, policy, scientific and philosophical considerations, that the risk such persons would pose, rather than their ca- pacity for criminal responsibility per se, may have significant legal and policy implications in England and Wales in the future. 7 Declaration No portion of the work referred to in the thesis has been submitted in support of an application for another degree or qualification of this or any other university or other institute of learning. 8 Copyright statement i. 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