Nitrous Oxide: What Do We Know about Its Use Disorder Potential? Results of the French Monitoring Centre for Addiction Network Survey and Literature Review

Background: Nitrous oxide (N 2 O) is used worldwide for analgesia and anesthesia. It is also used for recreational purposes by some people. N 2 O can have major side effects (myeloneuropathy, delusions, emphysema) when used to excess. In France, N 2 O is available as an equimolar mixture of oxygen and nitrous oxide (EMONO). Its substance use disorder potential is monitored by the French Monitoring Centre for Addiction (CEIP-A) network. Our objective is to provide an overview of the substance use disorder potential of N 2 O in general, and of EMONO in particular. Methods: This paper is based on a systematic review of the literature for case reports involving N 2 O use disorder and on CEIP-A network cases involving EMONO use disorder. We characterized use disorder in accordance with DSM-5 ( Diagnostic and Statistical Manual of Mental Disorders, 5th Edition ) criteria. Furthermore, we considered data relating to medical history, age, gender, and N 2 O consumption habits. Results: We identified 59 cases of N 2 O use disorder in the literature and 17 cases of EMONO use disorder from the CEIP-A network. More than 90% of the cases used N 2 O in larger quantities and for longer than intended. Conversely, more negative as opposed to positive cases have been documented regarding tolerance and failed attempts to reduce usage. Conclusions: A specific profile of substance use disorder starts to emerge from all the cases studied here. Furthermore, we identified another way N 2 O use disorder can appear: through exposure for medical purposes.