Integrating Non-Psychiatric Models of Delusion-Like Beliefs into Forensic Psychiatric Assessment

In both clinical and forensic psychiatry, it can often be difficult to distinguish delusions from normal beliefs. The categorical approach of the Diagnostic and Statistical Manual of Mental Disorders (DSM) leaves few options to describe intermediate delusion-like beliefs (DLBs). Neurocognitive models offer an alternative view of DLBs as existing on a continuum that can be quantified based on dimensions of severity as well as underlying cognitive biases. The Internet provides broadened access to putative evidence for diverse beliefs, with filter bubbles and echo chambers that can amplify confirmation bias and strengthen conviction. It is therefore much easier now for fringe beliefs to be shared and much less clear when they should be considered delusional. To place DLBs into a forensically relevant framework, psychiatric expert witnesses should adopt a broad biopsychosocial understanding of belief formation and maintenance that integrates clinical expertise with knowledge about dimensional aspects of delusions, cognitive biases, and the processing of online misinformation. The unavoidable conclusion that normal thinking is replete with cognitive biases and misbeliefs challenges the legal concept of mens rea that forms the foundation of a retributivist American justice system.