Post-traumatic stress disorder caused in mentally disordered offenders by the committing of a serious violent or sexual offence

The aim of the study was to measure in a sample of mentally disordered offenders the frequency of post-traumatic stress disorder (PTSD) symptoms related to the committing of an offence and to consider what factors might be contributory to the onset and maintenance of these symptoms. The study was the first to investigate the incidence of PTSD in a primarily mentally ill population. A sample of 37 mentally disordered offenders was assessed for PTSD according to the Diagnostic and Statistical Manual of Mental Disorders (DSM III-R; American Psychiatric Association, 1987) and the Impact of Events Scale (IES; Horowitz, Wilner and Alvarez, 1979). Of this sample, 33% met diagnostic criteria for PTSD and 54% had significant PTSD symptomatology as indexed by the IES. The IES scores were greater in those who had committed violent offences than in those who had committed sexual offences, and in those who had an affective diagnosis. Frequency of PTSD symptoms was greater in those offenders who now felt regret for their actions. The high frequency of PTSD symptoms in this population may serve as a significant stressor and may exacerbate co-morbid psychiatric illness and contribute to poor treatment response and relapse. Many mental illnesses are exacerbated by stress and the presence of untreated PTSD symptoms may serve to prevent treatment gains for the primary mental disorder. If risk of future dangerousness is associated with unstable mental state, as is often the case in a mentally disordered population, then the development of PTSD post-offence may serve to prolong or increase risk of harm to both self and others.