Introduction <p>Fabry disease is a rare X-linked lysosomal storage disorder characterized by α-galactosidase A enzyme deficiency, leading to systemic accumulation of glycosphingolipids. Among psychiatric symptoms, depression is the most frequently reported, while psychotic symptoms are extremely rare, with fewer than ten cases documented in the literature.</p> Case presentation <p>In the presented case, a 22-year-old female patient with a diagnosis of Fabry disease developed psychotic symptoms—including auditory hallucinations, persecutory and referential delusions, and disorganized behavior—approximately one week after discontinuing enzyme replacement therapy (ERT). A multidisciplinary evaluation revealed no acute pathology that could explain the psychotic presentation. ERT was reinstated, and olanzapine and fluoxetine were initiated to address her psychotic and obsessive symptoms, resulting in a partial clinical improvement and ongoing outpatient follow-up.</p> Discussion <p>This case highlights a temporal relationship between ERT discontinuation and the emergence of psychotic symptoms, suggesting a possible link with metabolic imbalance. Unlike previously reported cases where such symptoms were attributed to cerebrovascular complications, the current case points toward potential neurochemical mechanisms.</p> Conclusion <p>Clinicians should be aware that psychotic symptoms may emerge in Fabry disease, particularly in the context of treatment non-adherence. This case aims to enhance clinical awareness of rare neuropsychiatric manifestations in lysosomal storage disorders and underscores the essential role of a multidisciplinary approach in managing such complex presentations.</p>