BACKGROUND: Adverse childhood events (ACEs), psychopathy, and self-harming behaviours are prevalent among individuals in the forensic psychiatry system. While existing literature suggests that ACEs, self-harm, and psychopathy are interrelated, little is known about the interplay of psychopathic traits in this relationship. The present study aimed to determine the mediating role of psychopathy in the relationship between ACEs and self-harming behaviours in forensic patients.
METHODS: This was a retrospective study of patients under the Ontario Review Board (ORB) between 2014 and 2015. In the analysis, we included patients with complete data on ACEs, self-harming behaviours, and a Psychopathy Checklist-Revised (PCL-R) score - a measure of psychopathic traits and their severity conducted during the reporting period. Mediation analysis was based on the Baron and Kenny approach, and sensitivity analysis was performed based on the types of ACEs.
RESULTS: ​​​The sample population (n = 593) was made up of adults, with a mean age of 41.21 (± 12.35) years and were predominantly males (92.37%). While there was a partial mediating effect of psychopathy on the relationship between ACEs and incidents of self-harming behaviours in the past year, the mediation was complete in the relationship between ACEs and a lifetime history of self-harming behaviours. Following sensitivity analysis based on the types of ACE, the mediating effects were more attributed to specific ACEs, especially having experienced child abuse or having an incarcerated household member before 18 years.
CONCLUSIONS: Among forensic patients in Ontario, psychopathy mediates​ ​the relationship between experiencing ACEs and engaging in self-harming behaviours. Effective intervention to mitigate self-harming behaviours in this population should consider the potential role of psychopathy, especially among individuals who have experienced ACEs involving a history of child abuse and a family who was incarcerated.

In Canada, ensuring public safety, and the safety and well-being of accused individuals under the jurisdiction of the provincial review board are very important. While previous studies have reported a significant risk of self-harming behaviors (non-suicidal self-injury and suicide attempt) in forensic psychiatric settings, no large population study has assessed any relationship between forensic system-related factors and self-harming behaviors. A better understanding of these factors can help clinicians implement protective measures to mitigate self-harming behaviors or actions.
Using the Ontario Review Board (ORB) database covering 2014-2015 period (n = 1211, mean age = 42.5 ± 13.37 years, males = 86.1%), we analyzed the prevalence and factors associated with self-harming behaviors, emphasizing the characterization of the forensic system-related factors (ORB status, legal status, type of offense, previous criminal history, and victim relationship). The relationships between the forensic system-related factors and self-harming behaviors were explored using five separate logistic regression models, controlling for clinical and sociodemographic characteristics.
Approximately 4% of the individuals in the forensic system over the study period engaged in self-harming behaviors Among the studied patients, individuals determined to be unfit to stand trial and inpatients were significantly more likely to have self-harming behaviors. There was no significant relationship between the type of offence, victim relationship, and previous criminal history with self-harming behavior.
Forensic psychiatry inpatients should have close observation, screening, monitoring, and individual tailored management strategies for self-harming behaviors. The findings of this study indicate that forensic system-related factors, especially those that pertain to the status of individuals in the forensic system (i.e., unfit to stand trial and being an inpatient) are more responsible for self-harming behaviors among forensic patients in Ontario.