Electronic Thesis and Dissertation Repository


Master of Science




Dr. Peter N.S. Hoaken


Forensic psychiatric patients engage in more aggression than any other inpatient psychiatric population. Aggressive behaviour impedes rehabilitation, as aggressive individuals are often excluded from evidence-based therapies due to safety concerns. Dialectical behaviour therapy (DBT) is a group-based cognitive-behavioural psychotherapy designed to target maladaptive behaviours, such as aggression, in individuals who are behaviourally and emotionally dysregulated. The present study assessed whether six months of DBT is effective in reducing aggression, anger, and hostility in a representative, medium-security, forensic psychiatric population compared to treatment as usual. Participants (N = 17) suffered from a range of psychotic, personality, substance use, and mood disorders. Results suggest that DBT shows promise in reducing aggression, anger, and hostility in this population, however this is little evidence that the skills taught in DBT are responsible for those changes. The implications and future directions of this research are discussed.