Investigating the Impact of Past Trauma and Defense Styles on Posttraumatic Stress Following Homicide and Psychiatric Co-morbidity.

To examine the prevalence of PTSD following homicide and investigate the relationship between PTSD from past traumas, defense styles and PTSD following homicide and psychiatric co-morbidity. 167 male homicide perpetrators participated in the study and completed the Posttraumatic Stress Diagnostic Scale, the General Health Questionnaire-28 and the Defense Styles Questionnaire. 45% met the criteria for PTSD following homicide and 55% for no-PTSD. With the number of times for imprisonment adjusted, regression analyses showed that immature defense style was associated with PTSD following homicide with the severity of PTSD from past traumas as a moderator. Neurotic and immature defense styles and PTSD from past trauma were significantly and independently associated with psychiatric co-morbidity. Homicide perpetrators could develop PTSD following homicide. The severity of PTSD from past traumas could affect PTSD following homicide and other psychological problems, and influence the effect of using immature defense against PTSD from homicide. Past trauma, immature and neurotic defense styles had a unique and specific pattern of influence on psychological symptoms, other than trauma symptoms.