The delusional dimension of anorexia nervosa: phenomenological, neurobiological and clinical perspectives

Background: Delusional characteristics have been largely ignored in patients suffering from anorexia nervosa ( AN). Objectives: To review the literature on delusional features in AN from phenomenological, neurobiological, and clinical viewpoints. Methods: Data were obtained through searches of Medline, PubMed, SciELO and Cochrane Library. Results: Distorted beliefs in AN may range from an overvalued idea to an overt delusion, involving affective, personality and/or psychotic disorders. Studies confirm alterations in monoaminergic systems. It has also been seen a decreased integration of visual/proprioceptive information, and alterations in neural networks involved in body processing. It is known that body image distortion may present "delusional proportions" as a consequence of great concern about body. Concomitantly, "embodied defence hypothesis" has been proposed. Restrictive AN exhibits higher levels of delusionality, and a particular delusional type of AN has been suggested, associated with a worse long-term outcome. Low doses of atypical antipsychotics are recommended combined with cognitive techniques. Discussion: Delusional thinking in AN is likely a dynamic and dimensional phenomenon that can vary, both in nature and/or severity, whereas high insight levels, before and after refeeding, result in positive outcomes. Neurobiological research on this topic must be encouraged, since clinical and phenomenological approaches are comparatively more frequently reported.