Catatonia Secondary to Sudden Clozapine Withdrawal:A Case with Three Repeated Episodes and a Literature Review

A literature search identified 9 previously published cases that were considered as possible cases of catatonia secondary to suddenclozapine withdrawal. Two of these 9 cases did not provide enough information to make a diagnosis of catatonia according tothe Diagnostic and Statistical Manual, 5th Edition (DSM-5). The Liverpool Adverse Drug Reaction (ADR) Causality Scale wasmodified to assess ADRs secondary to drug withdrawal. From the 7 published cases which met DSM-5 catatonia criteria, usingthe modified scale, we established that 3 were definitive and 4 were probable cases of catatonia secondary to clozapine withdrawal.A new definitive case is described with three catatonic episodes which (1) occurred after sudden discontinuation of clozapine inthe context of decades of follow-up, (2) had≥3 of 12 DSM-5 catatonic symptoms and serum creatinine kinase elevation, and (3)required medical hospitalization and intravenous fluids. Clozapine may be a gamma-aminobutyric acid (GABA) receptor agonist;sudden clozapine withdrawal may explain a sudden decrease in GABA activity that may contribute to the development of catatonicsymptoms in vulnerable patients. Based on the limited information from these cases, the pharmacological treatment for catatoniasecondary to sudden clozapine withdrawal can include benzodiazepines and/or restarting clozapine.