Several reviews have reported the incidence of schizophrenia in patients with eating disorders (ED) to be between 3–10% and the incidence of transient psychotic episodes to be 10–15%. On the other hand, anorexia nervosa appears to affect 1 to 4% of schizophrenia patients. Reports of psychosis and ED occurring in the same patient have led to various views as to the nature of the relationship between the two.

Analysis of the literature illustrated by different clinical cases in which appears to be a relationship between ED and psychosis.

Critical reflection about the hypothesis that could underlie the comorbidity of psychotic illness and ED.

Non-systematic review of a literature search using the keywords: eating disorders; psychosis; comorbidity.

There is no consistent sequence in the co-occurrence of the two conditions – ED sometimes precede and sometimes follows the onset of psychosis. ED patients can develop psychotic symptoms, most frequently transient in the course of the disorder, while others are subsequently diagnosed with a chronic psychotic disorder. On the other hand, patients with a primary psychotic illness can develop an eating disorder. The connection between the two, however, remains speculative, considering the hypothesis that ED and psychosis can be entirely separate disorders that can, by chance, occur in the same person.

The area of comorbidity and overlapping symptoms in psychiatry requires more deep research. Despite evidence from case series, the comorbidity between ED and psychosis is poorly understood, and firm conclusions cannot be drawn from this analysis.

The authors have not supplied their declaration of competing interest.