Neuropsychiatric disorders associated with recreational nitrous oxide use.

Chronic recreational nitrous oxide use can cause functional vitamin B12 deficiency and neuropsychiatric complications. In a review of 16 patients aged 17–25, all had neurological symptoms like limb numbness, unsteady gait, and weakness; 12 also had psychiatric symptoms including hallucinations, agitation, depression, and personality changes. Twelve patients had vitamin B12 deficiency, and all 16 had elevated homocysteine levels. Fourteen showed abnormal spinal cord signals on MRI. Symptoms improved with vitamin B12 treatment and stopping nitrous oxide use. Clinicians should recognize nitrous oxide as a cause of neuropsychiatric problems in young adults.

Study at a glance

Abstract

Recreational nitrous oxide use has grown in popularity among young people and has become a serious public health problem. Chronic use of nitrous oxide can lead to a functional vitamin B12 deficiency and neuropsychiatric complications. This study aimed to investigate the characteristics of neuropsychiatric complications associated with nitrous oxide use and to enhance clinicians' awareness of this public health problem. We retrospectively reviewed 16 patients with neuropsychiatric disorders related to nitrous oxide use who were treated in our hospital from June 2021 to October 2022. Their demographics, clinical features, investigations, treatments and outcomes were analyzed. There were ten males and six females between the ages of 17 and 25 with a mean age of 20.5 ± 2.6 years. Thirteen patients sought medical help from the neurology clinic. Two patients presented to the psychiatric department and one patient presented to the emergency department with acute cognitive impairment. All 16 patients presented with neurological symptoms, such as paresthesia in four limbs or the lower limbs, unsteady gait and weakness. Twelve patients developed psychiatric symptoms, such as hallucinations, agitation, depression, emotional indifference and personality changes. Twelve patients had vitamin B12 deficiency. All 16 patients had hyperhomocysteinemia. Fourteen patients showed abnormal high signal on T2-weighted imaging and an inverted "V" sign in axial view, mainly involving the cervical cord. Neuropsychiatric symptoms improved with vitamin B12 treatment and cessation of nitrous oxide use in all cases. Young adults are predominately involved in recreational use of nitrous oxide, which can cause neuropsychiatric complications. The clinical response to vitamin B12 supplementation and cessation of nitrous oxide use is generally good. Clinicians should recognize nitrous oxide use as a public health problem and a cause of a wide range of neuropsychiatric symptoms, particularly in younger patients.