Abstract
BACKGROUND: Catatonia can arise from various conditions, not only psychiatric but also non-psychiatric etiologies. This diversity of underlying causes makes it challenging to identify the underlying etiology, which is crucial for appropriate management. Nitrous oxide (N(2)O) is widely used for recreational purposes, and its adverse effects have become a growing concern. Chronic exposure can lead to vitamin B12 deficiency, which manifests both neurological and psychiatric symptoms, including catatonia. Vitamin B12 supplementation is an effective treatment, but the diverse clinical manifestations of N(2)O toxicity, coupled with the diverse etiologies of catatonia, can delay diagnosis and intervention. CASE PRESENTATION: The patient, a healthy man in his 20s, had been receiving N(2)O anesthesia regularly for pain relief while undergoing cosmetic hair removal. After his seventh inhalation, he developed a catatonia and was admitted to a previous hospital. After a comprehensive examination failed to identify the etiology, he was transferred to our hospital for psychiatric assessment. Intravenous benzodiazepine failed to improve his catatonia. Re-evaluation of the underlying etiologies of benzodiazepine-refractory catatonia raised the possibility of a vitamin B12 deficiency resulting from chronic N(2)O exposure. Vitamin B12 supplementation promptly improved his catatonia, and the patient was discharged without any recurrence of his symptoms. CONCLUSION: Catatonia developed in the present patient after multiple exposures to N(2)O. Active vitamin B12 may be administered if N(2)O is suspected of causing psychotic symptoms. Moreover, reassessing the differential diagnosis is worthwhile when managing refractory catatonia.