States With Legal Weed See Drop in Mental Health Treatment

New research found a 37% decrease in those states

States that have legalized recreational marijuana use for adults have also seen a drop in mental health treatment admissions, according to newly published research.

The findings, which came in a study published last month in the journal Health Economics, were based on data from ten states that have legalized adult-use cannabis. 

“Recreational marijuana laws (RMLs) continue to grow in popularity, but the effects on mental health treatment are unclear,” wrote Alberto Ortega, a professor at O’Neill School of Public Health at Indiana University and the author of the study.

In the abstract, Ortega said that the study “uses an event-study within a difference-in-differences framework to study the short-run impact of state RMLs on admissions into mental health treatment facilities.” 

“The results indicate that shortly after a state adopts an RML, they experience a decrease in the average number of mental health treatment admissions,” Ortega wrote. “The findings are driven by white, Black, and Medicaid-funded admissions and are consistent for both male and female admissions. The results are robust to alternative specifications and sensitivity analysis.”

Ortega said “there is a clear, immediate, statistically significant decrease in total admissions” after a state adopts recreational marijuana laws, and that the “effect becomes more pronounced as time goes on and remains negative through event year four.”