Vexatious litigant vs paranoia querulans: A systematic review.

Introduction: Paranoia querulans is a type of persistent delusional disorder of the persecutory subtype, recognized under ICD-10 and DSM-IV. Being a classically described entity, evidence is lacking from its conceptualization as a nosological entity to diagnosis and treatment. Furthermore, controversy still exists regarding its interplay between the judicial and mental health systems. Objectives: To summarize current evidence and knowledge regarding Paranoia querulans on its conceptualization, ethiopathological explanations, therapeutical management and interface between psychiatry and the law. Methods: A systematic review was undertaken between June and October 2020 in the PubMed, Web of Science and Scopus databases according to PRISMA directive. Key-terms: ((querul* OR vexatious) AND (paranoia OR delusio* OR neuros* OR behavi* OR complai*) OR litig*) AND psychiatry. No language or time restrictions were established. Results: A total of 1648 studies were initially identified (PubMed: 679; WOS: 945; Scopus: 24; other: 0); after duplicates were removed, n=1381 studies remained. After screening title and abstract, 56 studies were included. Their main content was categorized into: 1. Conceptualization (n=26):Neurosis (n=5), psychosis (n=9), behavioral disorder (n=5); no psychiatric diagnosis (n=7). 2. Descriptive psychopathology (n=8) 3. Etiopathogenesis (n=9): Social or personality basis (n=3), culture (n=4), trauma (n=1), cognitive decline (n=1) 4. Management (n=1) 5. Psychiatry and Law: same object, different objectives (n=12) Conclusions: There is controversy regarding the nosological entity of querulousness, frompsychosis to neurosis or behavioral disorders. Someauthors consider this behavior to not be a psychiatric diagnosis. Furthermore, most papers dealtwith a social or nurture-based origin. There is a dearth of information regarding treatment. [ABSTRACT FROM AUTHOR]