Legalization of Cannabis Tied to Drop in Opioid-Related ED Visits

Megan Brooks

July 13, 2021

State laws permitting recreational marijuana use have not led to an increase in opioid-related emergency department (ED) visits, as many had feared.

On the contrary, states that legalize recreational marijuana may see a short-term decrease in opioid-related ED visits in the first 6 months, after which rates may return to prelegalization levels, new research suggests.

Previous research suggests that individuals may reduce the use of opioids when they have an alternative and that cannabis can provide pain relief.

"At the same time, we often hear claims from politicians that we should not legalize cannabis because it may act as a 'gateway drug' that leads to use of other drugs," lead researcher Coleman Drake, PhD, Department of Health Policy and Management, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, told Medscape Medical News.

"Our findings indicate that cannabis legalization does not effect any increase in opioid-related ED visits, contradicting the gateway drug explanation," Drake said.

The study was published online July 12 in Health Economics.

Significant Reduction

So far, 19 states have legalized recreational cannabis, meaning that nearly half of the US population lives in a state that allows recreational cannabis use.

The investigators analyzed data on opioid-related ED visits from 29 states between 2011 and 2017. Four states ― California, Maine, Massachusetts, and Nevada ― legalized recreational marijuana during the study period; the remaining 25 states did not.

The four states with recreational cannabis laws experienced a 7.6% reduction in opioid-related ED visits for 6 months after the law went into effect in comparison with the states that did not legalize recreational marijuana.

"This isn't trivial – a decline in opioid-related emergency department visits, even if only for 6 months, is a welcome public health development," Drake said in a statement.

Not surprisingly, these effects are driven by men and adults aged 25 to 44 years. "These are populations that are more likely to use cannabis, and the reduction in opioid-related ED visits that we find is concentrated among them," Drake told Medscape Medical News.

However, the downturn in opioid-related ED visits after making marijuana legal was only temporary.

"The effect dissipates after the first 6 months, perhaps because cannabis ultimately is not a treatment for opioid use disorder," Drake said.

Encouragingly, he said, the data show that opioid-related ED visits don't increase above baseline after recreational marijuana laws are adopted.

"We conclude that cannabis legalization likely is not a panacea for the opioid epidemic, but there are some helpful effects," Drake told Medscape Medical News.

The study was supported by the National Institute on Drug Abuse. The authors have disclosed no relevant financial relationships.

Health Econ. Published online July 12, 2021. Abstract

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