[A Delusion That Crawls: Ekbom Syndrome in Schizophrenia]

The objective of this case report is to present a clinical challenge encountered by a patient followed at the Institut universitaire en santé mentale de Montréal (IUSMM) Psychotic Disorders Program: the coexistence of Ekbom syndrome and schizophrenia. Schizophrenia and Ekbom syndrome (delusional parasitosis) are 2 distinct psychiatric entities, yet they share similarities regarding delusional conviction, lack of insight, and response to antipsychotic treatment. Ekbom syndrome can occur as a primary delusional disorder or as a secondary manifestation within the context of schizophrenia. The American Psychiatric Association's DSM-5 criteria distinguish schizophrenia by the presence of multiple psychotic symptoms and greater functional impairment, whereas Ekbom syndrome is defined by a single, systematized somatic delusion, often manifesting outside of psychiatric contexts and accompanied by less pervasive negative symptoms.