Suicide by sodium nitrite poisoning: Findings from the National Violent Death Reporting System, 2018–2020

Objectives
Suicide by sodium nitrite may be an emerging trend in the United States. Our mixed-methods study aims to: (1) describe the rates of suicides secondary to sodium nitrite self-poisoning in the United States between 2018 and 2020 and (2) characterize the use of sodium nitrite as a suicide method.
Methods
Using NVDRS data, descriptive statistics, population-based incident rates/year and incidence estimates across 50 states were calculated. An inductive thematic analysis characterized the use of sodium nitrite as a suicide method on review of medical examiner and law enforcement reports.
Results
260 incidents were identified as suicides secondary to self-poisoning with sodium nitrite/nitrate across 37 states and 1 territory—69% of which occurred in 2020. The typical victim was a white male student with a known depressive disorder and a history of suicidal thoughts (n = 120). The annual suicide rate using sodium nitrite increased from 0.01–0.09/100,000 person-years over the three-year period. Online forums were used to share knowledge on the procurement and preparation of sodium nitrite poisoning.
Conclusions
Sodium nitrite self-poisoning is an increasingly used planned suicide method among young people. Further studies are required to identify the impact of means safety interventions on the incidence of sodium nitrite self-poisoning incidents.