The Association Between Recreational Cannabis Legalization and Substance Use Treatment Admissions for Cannabis Misuse, 2010-2021.

Abstract

The increasing legalization of recreational cannabis use in the U.S. has raised concerns about its potential impact on public health, including frequent cannabis use and treatment-seeking behavior. Although previous studies have examined cannabis use prevalence, less is known about its association with utilization of substance use treatment. This study utilized data from the Treatment Episode Data Set - Admissions from 2010 to 2021. The study sample included all treatment admissions during the study period. Difference-in-differences models were built to examine the association between recreational cannabis law and cannabis-related treatment admissions. Stratified analyses were conducted by age, sex, and race/ethnicity to identify subgroup variations. Statistical analysis was conducted in 2024-2025. Among the 19,873,143 admissions included in this study, 54.7% were aged between 21 and 39 years, 65.8% were males, 62.8% were non-Hispanic White, 75.4% were unemployed or not in the labor force, and 13.5% were married. The proportion of cannabis-related treatment admissions decreased continuously throughout the study period from 18.7% in 2010 to 8.9% in 2021. Although recreational cannabis law was not associated with significant immediate changes in cannabis-related treatment admissions, we identified a delayed effect beginning in the fourth year after policy implementation. Stratified analyses revealed that recreational cannabis law had a significant impact on individuals classified as other (i.e., those not identifying as White, Black, or Hispanic). Recreational cannabis law was associated with a long-term increase in the treatment-seeking behavior among individuals with cannabis use. The impact was particularly large among racial and ethnic minority populations.