Neuropsychiatric sequelae of chronic nitrous oxide misuse in middle‐aged adults: A case series

BACKGROUND AND OBJECTIVES: O) misuse causes heterogeneous neuropsychiatric toxicity. METHODS: O misuse and neuropsychiatric presentations. RESULTS: Presentations included cognitive impairment, hallucinations, and variable neurologic dysfunction. Homocysteine was markedly elevated in all patients, while vitamin B12, methylmalonic acid, hematologic indices, and longitudinal outcomes varied. DISCUSSION AND CONCLUSIONS: These cases illustrate heterogeneous biochemical and clinical trajectories, with biochemical abnormalities not consistently corresponding to clinical severity or recovery. SCIENTIFIC SIGNIFICANCE: O exposure in unexplained neuropsychiatric presentations and interpret cobalamin-related biomarkers in clinical context.