Psychiatric comorbidities in patients with anorexia nervosa: a narrative selective review

Anorexia nervosa (AN) is one of the most common eating disorders with multiple psychiatric comorbidities. This review aims to bring together the recent data on the most frequently coexisting with AN psychiatric nosologies including: body dysmorphic disorder (BDD), borderline personality disorder, non-suicidal self-injury, anxiety disorder, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), autism spectrum disorders (ASDs), major depressive disorder, bipolar disorder (BD) and checking behavior (CB). For the current review, PubMed was used to conduct an automated search for all studies on anorexia nervosa and its psychiatric comorbidities that were published between 2017 and 2023. The results of this review indicate that for many of these comorbidities there is strong evidence of an association between the conditions. To date there is no clear answer to the question if there is a common cause for these comorbidities, despite the numerous studies for similarities between their pathomorphology, such as similar patterns of activation of brain areas explored by functional magnetic resonance imaging (fMRI). A contributing factor could be that the application of the current criterial approach creates a substantial overlap of symptoms between different diagnostic groups. Based on the current review, it can be concluded that due to the frequent changes in the diagnostic criteria and their subjectivity, the main problems in the diagnosis and treatment of anorexia nervosa and its psychiatric comorbidities are the nosological problem. Further study is needed to explore the reasons behind the high frequency of coexistence of AN with other psychiatric disorders and how this may affect the treatment process.