Homicide followed by Suicide. An empirical analysis Liem, M.C.A. Homicide followed by Suicide. An empirical analysis Dissertation Utrecht University, the Netherlands. Including references and summaries in Dutch and Spanish. The printing of this thesis was funded by the Wiarda Dissertation Fund. ISBN: 978 90 902 4923 0 NUR: 741 Cover design: Omniafausta Editing: Wieneke Matthijsse Printed by: Ridderprint © Copyright M.C.A. Liem, 2010 Homicide followed by Suicide. An empirical analysis Doding gevolgd door zelfdoding. Een empirische analyse (met een samenvatting in het Nederlands) Homicidio seguido de suicidio. Analisis empirico (con un resumen en español) Proefschrift ter verkrijging van de graad van doctor aan de Universiteit Utrecht op gezag van de rector magnificus, prof. dr. J.C. Stoof, ingevolge het besluit van het college voor promoties in het openbaar te verdedigen op vrijdag 19 februari 2010 des middags te 12.45 uur door Marieke Christine Agatha Liem geboren op 16 december 1982 te Goes Promotores: Prof. Dr. F. Koenraadt Prof. Dr. P. Nieuwbeerta Preamble The human life cycle typically ends by four types of death: natural, accidental, suicidal or homicidal.i This doctorate thesis addresses events in which a combination of two types of death occurs: homicide followed by suicide of the perpetrator. In this event, one person causes the lives of at least two people to end. On a sunny afternoon several years ago, I asked Frans Koenraadt, by then my supervisor on my Master’s thesis in Clinical Psychology, whether he had some ideas for future research. He pointed to a dusty archive cabinet filled with cases on child homicide that needed further investigation. These cases stemmed from the Pieter Baan Centre, a psychiatric observation hospital for forensic mental health assessment in The Netherlands where I was doing an internship at that time. During the study of child homicide cases, I became very much intrigued by specific types of child homicide, such as familicide and homicide‐suicide. My interest in homicide‐suicide was further fuelled by talking to those directly and indirectly involved in these acts, such as police investigators, surviving family members as well as perpetrators who aimed to end their lives after committing homicide, but somehow failed to do so. Over the years, I continued to study several types of domestic homicide, including intimate partner homicide and other family homicide. I further modified and fine‐tuned the topic of homicide‐suicide in my MPhil dissertation in Criminological Research at the University of Cambridge, which provided the foundation of the doctorate thesis at hand. As it is with any written data, specifically large‐size datasets, it is a challenge not to become completely detached from the sources the figures were based on. In such settings, people easily become ‘numbers’: homicides tend to become abstract entities when coded into zeros and ones. While researching the homicide‐suicide phenomenon, I have tried not to lose the ‘human face’ of these events by listening to those involved before, during and after the act. A number of people have particularly contributed to the preparation of this doctorate thesis. First, I would like to extend my gratitude to Frans Koenraadt, who has introduced me to the field of forensic mental health with dedication, passion, and continuing encouragement. With sensitivity and attention for detail he patiently read and commented on numerous versions of this manuscript. In addition, I am very i Bhatia, S.C., et al., (1987) High risk suicide factors across cultures International Journal of Social Psychiatry 33, 226‐236. v Preamble grateful for the help of Paul Nieuwbeerta, whose insightfulness and ability to put large amounts of information into a comprehensive perspective prevented me from loosing focus while helping me to enhance my thoughts. I am grateful to Catherine Barber from the Harvard Injury Control Research Center for her critical views and willing support. I would also like to express my gratitude to Jack McDevitt, director of Northeastern University’s College of Criminal Justice, whose kindness and professional network assisted me in every way possible. A warm thanks to James Alan Fox and Jack Levin from Northeastern University for their cooperation and helpful attitude. I am also appreciative of the advice given by Carolyn Harris Johnson on previous versions of this manuscript. I would like to thank Ingeborg Deerenberg from Statistics Netherlands and Michiel Hengeveld, chairman of the Department of Psychiatry at Erasmus Medical Centre, for their aid in data collection. In addition, I am indebted to Rutger Vandenberg, Orlaith King, Kim Geene and Paula Stassen, for language correction and proofreading. Their alert editing saved me from cloudy sentences. If some have been overlooked, the responsibility is mine alone. Finally, I wish to express my gratitude to my parents, my brothers and Jesper, for their constant love, wisdom and understanding. Boston, MA October 2009 vi Overview 1 Introduction 1 Part I Background 2 Review of the Empirical Literature on Homicide‐Suicide 31 3 Review of Theories on Homicide‐Suicide 67 Part II The Epidemiology of and the Variation in Homicide­Suicide 4 Nature and Incidence of Homicide‐Suicide in the Netherlands 87 5 Homicide‐Suicide in Three Countries: The Netherlands, Switzerland and the United States 101 6 Intrafamilial Homicide‐Suicide Compared to Extrafamilial Homicide‐Suicide 111 Part III Homicide­(Para)Suicide Compared to Homicide and (Para)Suicide 7 Homicide‐Suicide Compared to Homicide and Suicide: A Macro Level Approach 123 8 Homicide‐Parasuicide Compared to Homicide and Parasuicide: A Meso Level Approach 135 9 Homicide‐Parasuicide Compared to Homicide and Parasuicide: A Micro Level Approach 153 Part IV Integration of Concepts 10 Conclusion 173 vii Table of Contents Preamble v Overview vii Table of contents ix Chapter 1 Introduction 1 1 Research topic and aims 1 2 What do we (not) know about homicide? 3 2.1 Homicide characteristics 3 2.2 Previous homicide research 4 2.3 Shortcomings in homicide research 5 3 What do we (not) know about suicide? 5 3.1 Suicide characteristics 6 3.2 Previous suicide research 7 3.3 Shortcomings in suicide research 7 4 Empirical knowledge on homicide‐suicide 7 4.1 Homicide‐suicide characteristics 8 4.2 Previous homicide‐suicide research 8 4.3 Shortcomings in empirical homicide‐suicide research 9 4.4 Difficulties in studying homicide‐suicide 9 5 Theories on homicide‐suicide 10 5.1 Shortcomings of the current theories on homicide‐suicide 14 6 This study 14 6.1 Research questions 14 6.2 Research strategy and design 16 7 Empirical data used 17 7.1 Data sources used to describe the characteristics of homicide‐suicide 17 7.2 Data sources used to compare homicide‐suicide with homicide and suicide 20 8 Scientific relevance and contribution of this study 24 9 Societal relevance of this study 25 10 Outline of this study 26 ix Table of contents Part I Background Chapter 2 Review of the Empirical Literature on Homicide­Suicide 31 1 Studies describing the variation in homicide‐suicide rates 31 2 Studies explaining the variation in homicide‐suicide rates 33 3 Studies describing homicide‐suicide characteristics 35 4 Studies disaggregating homicide‐suicide into various types 38 5 Studies on intimate partner homicide‐suicide 40 5.1 General 40 5.2 Amorous jealousy 42 5.3 Declining health 46 6 Studies on child homicide‐suicide 47 7 Studies on family homicide‐suicide 52 8 Studies on other family homicide‐suicide 54 8.1 Parent homicide‐suicide 54 8.2 Sibling homicide‐suicide 58 9 Studies on extrafamilial homicide‐suicide 59 10 Conclusion 64 Chapter 3 Review of Theories on Homicide­Suicide 67 1 Origin of aggression 68 1.1 Neurobiological theories 68 1.2 Strain theories 70 2 Direction of aggression: homicide or suicide 72 2.1 Attribution theory 72 2.2 Stream analogy for lethal violence 73 3 Outcome of aggression: homicide‐suicide over homicide or suicide 75 3.1 Psychodynamic theory 75 3.2 Psychopathological perspectives 77 3.3 Psycho‐evolutionary theory 81 3.4 Social integration theory 82 4 Conclusion 83 Part II The Epidemiology of and the Variation in Homicide­Suicide Chapter 4 Nature and Incidence of Homicide­Suicide in the Netherlands 87 1 Introduction 87 2 Methodology 87 3 Results 88 3.1 Incidence 88 3.2 Case characteristics 89 3.3 Victims 92 x Table of Contents 3.4 Perpetrators 95 4 Discussion 95 4.1 Limitations 95 4.2 Findings 95 5 Conclusion 98 Chapter 5 Homicide­Suicide in Three Countries: The Netherlands, Switzerland and the United States 101 1 Introduction 101 1.1 Cross‐national differences 102 2 Methodology 103 3 Results 104 3.1 Incidence 104 3.2 Case characteristics 105 3.3 Victims 105 3.4 Perpetrators 106 4 Discussion 107 4.1 Limitations 107 4.2 Findings 108 5 Conclusion 110 Chapter 6 Intrafamilial Homicide­Suicide Compared to Extrafamilial Homicide­Suicide 111 1 Introduction 111 2 Methodology 111 3 Results 112 3.1 Sample characteristics 112 3.2 Intrafamilial homicide‐suicide versus extrafamilial homicide‐suicide 114 4 Discussion 116 4.1 Limitations 116 4.2 Findings 117 5 Conclusion 118 Part III Homicide­(Para)Suicide Compared to Homicide and (Para)Suicide Chapter 7 Homicide­Suicide Compared to Homicide and Suicide: A Macro Level Approach 123 1 Introduction 123 2 Theoretical background 123 3 Methodology 124 4 Results 125 4.1 Homicide‐suicide versus homicide and suicide 125 xi Table of contents 4.2 Comparing subgroups 129 5 Discussion 130 5.1 Limitations 130 5.2 Findings 130 6 Conclusion