This book examines the South Australian Forensic Mental Health population in the context of Post-Traumatic Stress Disorder (PTSD), and other comorbid disorders such as illicit substance use, depression, and childhood trauma. The aim of the book is to examine the frequency of PTSD in perpetrators of homicide and other serious offences in a forensic mental health population. This is a small study with a cohort of 39 forensic patients who were admitted to the state-wide forensic mental health service. Each participant was interviewed using the Clinician Administered PTSD Scale (CAPS), the PTSD Checklist (PCL), the Centre for Epidemiological Studies on Depression (CES-D), and other tools. The results showed that patients identified on average eight major stressful events which often included their own offence; 33% (n=13) of patients had PTSD and 21% (n=8) severe PTSD. Most patients had major comorbid symptoms with 90% of the sample (n=35) having tried drugs, and 72% of the sample (n=28) had taken drugs more than 100 times. It explores real case studies the role of crime types and how they relate to trauma, for example killing strangers, or killing a family member such as a child.