From diagnosis to detention: examining structural bias in the Ontario forensic system

In Canada, psychiatrists serve as both treatment providers and forensic evaluators for the same patients. This occurs most often in forensic settings that are mandated to deliver care under review boards, leading to information that is shared across clinical and legal spheres. Through analysis of two illustrative composite cases constructed from three NCR cases within Ontario's forensic system, we examine how the merging of treatment and forensic roles can introduce systematic bias into forensic assessment and testimony. These composites reveal how confirmation bias, diagnostic anchoring, the availability heuristic, and other biases operate through cumulative unredacted reports to review boards, merged treatment and evaluation teams, combined fitness and criminal responsibility assessments, and the use of a single psychiatrist across separate tribunals. One case demonstrates how a misdiagnosis of schizoaffective disorder persisted for years resulting in a false positive. The other shows how genuine psychotic illness was misattributed to personality factors demonstrating a false negative. Ontario's system contains design features that favor diagnostic persistence over revision with few structural checkpoints at which a formulation must be independently re-examined. We further argue that diagnostic formulation carries more weight inside Canadian forensic institutions than elsewhere in the criminal justice system not only because an evaluator in this system must treat, but because of the structure of the Criminal Code itself. Specifically, while a mental disorder is required for the NCR defence, discharge from supervision is related to a reduction in violence - through treatment. Meaningful reform requires separation of treatment and evaluation roles, independent assessments, and possible legislative review, particularly given that NCR supervision is indeterminate. Without change, legal decisions will continue to be based on compromised information, undermining both justice and psychiatric care.