Psychiatric and Other Medical Manifestations of Nitrous Oxide Abuse: Implications From Case Series

BACKGROUND: Nitrous oxide (N2O), a commonly used anesthetic agent in dentistry, has emerged as a global public health threat in young population. Although N2O-related neurological sequelae such as spinal cord degeneration and sensorimotor peripheral neuropathy are well known, psychiatric manifestations of heavy N2O use remain unclear. Here, we presented 7 treatment-seeking patients with severe N2O use disorder to delineate the psychiatric profiles of N2O users in Asia. METHODS: Seven patients with severe N2O use disorder who sought treatment in Taipei City Psychiatric Center between 2017 and 2018 were enrolled. We used chart review method to retrospectively collect their clinical information including sociodemographics, psychiatric and substance history, urine toxicology findings, and treatment course. RESULTS: These N2O users all had diagnoses of severe N2O use disorder. They usually initiated N2O use in late adolescence and early adulthood. Six of them had histories of mood disorders; all of them reported other illicit substance use before using N2O. The main reasons for treatment seeking were irritability, psychotic symptoms, self-harm, or violent behaviors as four of them were given a diagnosis of substance-induced psychotic disorder. Urine drug screen showed negative for other illicit drug use except for 1 positive case for cannabis and 1 for amphetamine. Three of 7 cases were hospitalized because of the severity of their psychiatric symptoms and suicidal risk. CONCLUSIONS: These cases with severe N2O use disorder showed high prevalence of psychotic symptoms and dangerous behaviors such as suicide or violence. This study highlights the addiction potential of N2O and its related adverse consequences in the psychiatric aspect.