Forensic Psychiatry versus the Varieties of Delusion-Like Belief

The available categorical constructs within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, do not allow forensic psychiatrists to distinguish easily between the varieties of delusion-like belief. This dilemma is especially challenging when seemingly delusional beliefs are shared online. Although the term "extreme overvalued belief" has been proposed to aid with such distinctions, its definition has conceptual problems, including diagnostic overlap with shared delusions, "extremism" that refers to behavior rather than belief, and the potential to be applied with prosecutorial bias to thwart defense strategies attempting to establish connections between criminal behavior and less than optimal mental health. Beliefs and behavior that are not obviously symptomatic of mental illness are best explained by integrating psychiatric expertise with that of other disciplines such as psychology, sociology, and political science. Dimensional quantification of belief conviction and preoccupation as well as established concepts like conspiracy theories and sacred values can help forensic evaluators characterize ideological motives for deviant behavior more accurately to better inform legal decisions about criminal responsibility and therapeutic justice.