Threat assessment professionals and forensic mental health experts face a challenging differential in determining whether a potential violent actor or postviolence defendant suffers from a delusional disorder or is simply radicalized in his extreme religious or political beliefs. No published model for analysis (i.e., structured professional judgment, SPJ) is available to aid in systematically distinguishing these cases or promoting transparency in associated reports and testimony. In the model of analysis (SPJ) proposed herein, 7 primary arenas of analysis were distilled from scholarship regarding features of delusions and delusional disorder: belief content; belief style; subjective distress and social dysfunction associated with the belief; social influences in belief formation, maintenance, and behavior; social inclusion; prodromal factors; and behavioral or action factors. Seventeen factors are specified for operationally defining and qualitatively describing the 7 primary arenas of analysis. Within each factor, features may be specified that further disaggregate the analysis. This SPJ tool is termed: Model of Analysis for Differentiating Delusional Disorder from the Radicalization of Extreme Beliefs–17 Factor (MADDD-or-Rad-17). (PsycINFO Database Record (c) 2018 APA, all rights reserved)