Since the process of deinstitutionalisation, increasing numbers of those with mental disorder are coming into contact with the criminal justice system. As such, police officers are required to be able to effectively interview this vulnerable cohort in an appropriate manner to elicit accurate and reliable information. However, there is a lack of psychological research that explores the vulnerable suspect during the investigative interview. This is concerning given that those with a mental disorder are at a heightened risk of providing misleading information and falsely implicating themselves. The current thesis sets to address this. Exploring police officers’ perceptions of mental disorder indicated that there is still a lack of understanding of what constitutes a mental disorder, and that the level of experience the officer has impacts upon their perceptions of this vulnerable group. Thus, the treatment and outcome of the MD suspect is heavily dependent on whom they encounter. Further studies explored the actual interviewing of MD suspects by examining real-life transcripts, and via experimental methods. Results indicated that current practice may not be best for interviewing the MD suspect; that is, one size may not fit all in terms of questioning style. Other work explored the efficacy of the current safeguards utilised within the investigative interview; here it was found that Appropriate Adults continue to remain passive in their approach, thus not fulfilling their role as part of the Police and Criminal Evidence Act. Finally, the introduction of the Forensic Interview TraceÓ is outlined as a standardised structure for police officers to effectively evaluate their interviews in order to ensure their skillset does not decline, especially when one considers the complexities involved when interviewing MD suspects. Implications are discussed throughout in relation to relevant theoretical and empirical work, as well as applications and potential impact of the research
