Constructing a defence of insanity: the role of forensic psychiatrists

Abstract

This thesis explores the role of forensic psychiatrists as expert witnesses in criminal trials using the insanity defence in New Zealand. It relies on data generated through qualitative research methods and provides thick descriptions‘ of how the role works in practice as forensic psychiatrists, together with the instructing lawyers, construct the defence. Multiple data sources were accessed, including thirty-one interviews with lawyers and forensic psychiatrists, observation of a high profile criminal case, and interpretation of clinical and legal texts. The research extends the existing medico-legal literature that has studied the relationship between psychiatry and law and provides analysis which contributes to current debates around the use of psychiatric expertise in cases of insanity. Drawing on contemporary socio-legal studies, the research focuses on the hybrid nature of the insanity defence, the hybrid expertise forensic psychiatrists‘ practise as expert witnesses, and the symbiotic relationship between lawyers and forensic psychiatrists that occurs in this context. This thesis argues that the insanity defence is a hybrid construct that brings lawyers and forensic psychiatrists together in such a way that the boundaries, which should ideally define their discrete functions, become blurred. The way the insanity defence shapes forensic psychiatrists‘ practices, and the relationship between lawyers and forensic psychiatrists, is also explored. The forensic psychiatrists‘ practices are shown to be inextricably linked to the legal requirements for an expert witness and the defence of insanity. From this perspective, the forensic psychiatrists are not ―doing psychiatry‖ as they would in a therapeutic setting, but rather they practise a hybridised expertise that reflects the hybrid nature of the insanity defence. The symbiotic relationship that occurs in practice as lawyers and psychiatrists make a case for insanity is demonstrated. This implicates lawyers in the production of effective expert testimony and illustrates how the defence of insanity is co-produced by both professionals in the courtroom. This thesis highlights how the boundaries that aim to separate the responsibilities of forensic psychiatrists, lawyers and fact-finders become blurred in practice. It contends that these findings have significant implications for not only the continued use of forensic psychiatrists in cases of insanity, but also public understandings of madness.