A consensus document on definition and diagnostic criteria for orthorexia nervosa
Authors: Donini Lorenzo M. , Barrada Juan Ramón , Barthels Friederike , Dunn Thomas M. , Babeau Camille , Brytek-Matera Anna , Cena Hellas , Cerolini Silvia , Cho Hye-hyun , Coimbra Maria , Cuzzolaro Massimo , Ferreira Claudia , Galfano Valeria , Grammatikopoulou Maria G. , Hallit Souheil , Håman Linn , Hay Phillipa , Jimbo Masahito , Lasson Clotilde , Lindgren Eva-Carin , McGregor Renee , Minnetti Marianna , Mocini Edoardo , Obeid Sahar , Oberle Crystal D. , Onieva-Zafra Maria-Dolores , Opitz Marie-Christine , Parra-Fernández María-Laura , Pietrowsky Reinhard , Plasonja Natalija , Poggiogalle Eleonora , Rigó Adrien , Rodgers Rachel F. , Roncero Maria , Saldaña Carmina , Segura-Garcia Cristina , Setnick Jessica , Shin Ji-Yeon , Spitoni Grazia , Strahler Jana , Stroebele-Benschop Nanette , Todisco Patrizia , Vacca Mariacarolina , Valente Martina , Varga Màrta , Zagaria Andrea , Zickgraf Hana Flynn , Reynolds Rebecca C. , Lombardo Caterina 
Published: November 2022

Abstract
Purpose
Since the term orthorexia nervosa (ON) was coined from the Greek (ὀρθός, right and ὄρεξις, appetite) in 1997 to describe an obsession with “correct” eating, it has been used worldwide without a consistent definition. Although multiple authors have proposed diagnostic criteria, and many theoretical papers have been published, no consensus definition of ON exists, empirical primary evidence is limited, and ON is not a standardized diagnosis. These gaps prevent research to identify risk and protective factors, pathophysiology, functional consequences, and evidence-based therapeutic treatments. The aims of the current study are to categorize the common observations and presentations of ON pathology among experts in the eating disorder field, propose tentative diagnostic criteria, and consider which DSM chapter and category would be most appropriate for ON should it be included.

Methods
47 eating disorder researchers and multidisciplinary treatment specialists from 14 different countries across four continents completed a three-phase modified Delphi process, with 75% agreement determined as the threshold for a statement to be included in the final consensus document. In phase I, participants were asked via online survey to agree or disagree with 67 statements about ON in four categories: A–Definition, Clinical Aspects, Duration; B–Consequences; C–Onset; D–Exclusion Criteria, and comment on their rationale. Responses were used to modify the statements which were then provided to the same participants for phase II, a second round of feedback, again in online survey form. Responses to phase II were used to modify and improve the statements for phase III, in which statements that met the predetermined 75% of agreement threshold were provided for review and commentary by all participants.

Results
27 statements met or exceeded the consensus threshold and were compiled into proposed diagnostic criteria for ON.

Conclusions
This is the first time a standardized definition of ON has been developed from a worldwide, multidisciplinary cohort of experts. It represents a summary of observations, clinical expertise, and research findings from a wide base of knowledge. It may be used as a base for diagnosis, treatment protocols, and further research to answer the open questions that remain, particularly the functional consequences of ON and how it might be prevented or identified and intervened upon in its early stages. Although the participants encompass many countries and disciplines, further research will be needed to determine if these diagnostic criteria are applicable to the experience of ON in geographic areas not represented in the current expert panel.

Level of evidence
Level V: opinions of expert committees