Vitamin B12 Deficiency Masquerading as Clozapine-Resistant Psychotic Symptoms in Schizophrenia

Abstract

To the Editor: Vitamin B12 deficiency, although known to be associated with neuropsychiatric manifestations of varying nature, is an underdiagnosed entity. We present a case of Vitamin B12 deficiency manifesting as clozapine-resistant symptoms in a patient with schizophrenia, in the absence of any clinical signs of vitamin B12 deficiency. The patient showed significant clinical improvement with parenteral vitamin B12 supplementation. This case highlights the need for vitamin B12-level assessment in such cases, as it could play a significant role in determining the outcome of the psychiatric disorder. Vitamin B12 deficiency, an often under-diagnosed condition, is associated with various neuropsychiatric manifestations. Psychiatric manifestations can be associated with vitamin B12 deficiency. These include depression, irritability, dementia, delirium, and hallucinations.1 There have been reports of B12 deficiency presenting as psychosis2,3 or as catatonia.4,5 The onset of the psychotic symptoms can occur after,2 in the presence of3,6 or in the absence5 of any overt clinical examination findings indicative of vitamin B12 deficiency. We present a patient with signs of clozapine-resistant schizophrenia in whom there were no overt clinical signs or symptoms of vitamin B12 deficiency but who had low serum B12 levels. This patient improved significantly with parenteral vitamin B12 supplementation.