Cannabis Policies, Cannabis, and Opioids in Suicide and Undetermined Intent Death

Suicides and deaths of undetermined intent frequently involve cannabis or opioids, yet the relationships between cannabis and opioids, and cannabis policies and cannabis or opioid involvement in these deaths, are not well-characterized. Additionally, although there have been substantial changes to cannabis policies, there have been conflicting findings on relationships between changing cannabis policies and cannabis-involved or opioid-involved deaths.

This was a repeated, cross-sectional study of decedents using restricted access data from the National Violent Death Reporting System from 2003 to 2018 and the Cannabis Policy Scale. The following associations were assessed among decedents from suicide and deaths of undetermined intent using mixed effects logistic regression: (1) relationships between cannabis involvement and opioid involvement; (2) relationships between cannabis policies and cannabis involvement; and (3) relationships between cannabis policies and opioid involvement. Analyses were conducted from 2021 to 2022.

States contributing to National Violent Death Reporting System increased in number from 7 to 41 throughout the study period, and the final sample included 68,924 decedents of suicide and undetermined intent. Cannabis involvement was associated with increased odds of opioid involvement (AOR=1.29, 95% CI=1.22, 1.37). A 10% increase in Cannabis Policy Scale, representing a more restrictive cannabis policy environment, was associated with reduced odds of cannabis involvement (AOR=0.87, 95% CI=0.84, 0.90) and opioid involvement (AOR=0.88, 95% CI=0.85, 0.91).

These findings do not support the idea that cannabis policy liberalization and/or cannabis use are likely to be useful strategies to reduce cannabis or opioid involvement in deaths of suicide and undetermined intent.