Perihomicidal reactions of homicide offenders : a dynamic appraisal of the expression and experience of homicide

Given the necessity for accurate, process-oriented analysis of homicidal experiences, the present research employed a guided imagery methodology to investigate the perihomicidal experience of a sample of homicide offenders incarcerated in Tasmania, Australia. The study employed 22 participants who had committed at least one act of homicide, with murder being their index offence. The aims of this thesis were threefold: firstly, to investigate the experience and expression of homicide as it occurred for the offender, that is, perihomicidal, and compare this experience from their response to anger-inducing and threatening events; secondly, to examine the psychological and psychophysiological responses of homicide perpetrators as the offence unfolded across time, providing a dynamic analysis of the homicidal act; and thirdly, to explore a number of group variables that may mediate the experience and expression of homicide. To meet these aims, the current investigation used an extended case study design. However, data were analysed according to a number of group variables identified within the existing research literature, these being psychopathy, antisocial personality disorder, instrumentality-expressiveness, victim-offender relationship, and offence characteristics, being homicidal role and co-offending. Together with psychophysiological data (heart rate, respiration), psychological data were also collected for analysis (visual analogue scales measuring perihomicidal psychological reactions, MCMI-111, STAXI-11, PCL: SV) providing both objective and subjective measurement of perihomicidal experience. The findings of the current research supported the complexity of homicide and the heterogeneity of the offenders who perpetrate these behaviours. Study One examined all participants, comparing their homicidal act with control events. It concluded that perihomicidal response can be distinguished from anger inducing and threatening events, but that the experience and expression of homicide differs between offenders. Study Two examined the potentially mediating effect of psychopathy and antisocial personality disorder on perihomicidal response. Importantly, this study demonstrated the clear differentiation between the response profiles of homicide perpetrators who are categorized ~s psychopathic or antisocial compared with those who have no (diagnosed personality disorder. Moreover, the results add strength to the view that psychopathy and antisocial personality disorder are distinct constructs that should be considered separately in any analysis of homicide. The merit in subcategorizing psychopathic personalities is also discussed. Study Three examined the classic instrumental-expressive dichotomy in relation to homicide motivation. The results provided some evidence that psychological and psychophysiological, perihomicidal response can be differentiated on the basis of instrumental versus expressive motivation, however, the results were inconclusive and the limitations are discussed accordingly. Study Four examined the possible mediating impact of victim-offender relationship on the psychological and psychophysiological response profiles of homicide offenders. Although the results demonstrated that the offenders who knew their homicide victims displayed higher overall autonomic arousal across all scripts, their perihomicidal experience was not distinguishable from those offenders whose victims were strangers on the basis of their psychological response. Study Five investigated the perihomicidal reactions of offenders as a function of the role played by the offender in their homicidal behaviours. The findings suggest that apart from overall intensity of arousal to the imaged homicide being greater in the active group, there was no other mediating effect of homicide role. Furthermore, the groups were indistinguishable based on their psychological perihomicidal response, psychopathology and clinical profile. Finally, in Study Six the role played by co-offenders in mediating the experience of homicide for one another is examined. Results confirmed that there exists some mediating impact of co-off ending on the perihomicidal experience. There are a number of limitations to the research presented in this thesis. The sample was 'limited to males, to apprehended offenders, and in participant numbers, and thus may not have contained a full range of homicide examples which may limit the generalisability of the findings. The implications of the present findings are discussed in relation to the existing literature on homicide and to the practical implementation of guided imagery for homicide within a justice system framework, for example, the utilisation of this methodology in forensic assessment.