As Congressional Democrats push for cannabis legalization at the federal level, a new University of Pittsburgh study further throws water on the notion that marijuana is a so-called “gateway” drug.
For decades, public health education programs and anti-legalization advocates have warned that marijuana use leads people to experiment with other more deadly and addictive substances, such as opioids. This talking point has significant public health implications due to the ongoing overdose epidemic.
“We don’t find any evidence to support the theory that cannabis functions as a gateway drug...if anything, we find that recreational cannabis legalization decreases opioid-related emergency department visits,” said lead author Coleman Drake, an assistant professor specializing in health policy and management at Pitt’s Graduate School of Public Health.
Drake and his team looked at state-level aggregate data from California, Maine, Massachusetts and Nevada, which all legalized marijuana at the start of 2017. For half of 2017, these states saw a 7.6 percent decline in opioid-related visits when compared to states where recreational use was illicit. After six months, the rate of the opioid-related ER visits reverted back towards the level it was at prior to legalization.
While the reduction in opioid-related ER visits was temporary, Drake argues that it’s still substantial. Because researchers had access to only one year of data, he plans to return to the topic to see how the effects of legalization play out over a longer period of time.
The study makes no definitive conclusions as to why legalization has this effect, nor why it was temporary. But Drake noted that some people start using opioids due to chronic pain, and then become addicted.
“Cannabis is a substitute for pain relief, but it’s not a treatment for opioid use disorder,” said Drake. “People might be finding that cannabis does help treat pain for opioid use disorder, but ultimately isn’t treating other symptoms of the condition.”
That causes people to return to opioids.
The findings indicate a possible need for more robust access to addiction treatment options that use medications, such as methadone and buprenorphine, to blunt opioid cravings. Abstinence-only recovery programs often oppose the use of these medications, despite a growing body of evidence that shows medicated-assisted treatment improves outcomes.
It’s hard to draw too many conclusions from this study, cautioned Alice Bell of Prevention Point Pittsburgh, a nonprofit specializing in drug user health and harm reduction.
“This data hopefully once and for all puts a nail in the coffin that marijuana is a 'gateway drug,' ” said Bell. “It would be useful to do qualitative research and ask people who use drugs what they are actually doing.”
Drake agreed that this would be a good path of inquiry. Still, he hopes that his findings will build on the public’s understanding of the effects of legalization, which is a relatively new phenomenon.
“The kicker with a lot of recreational cannabis research at this point in time is that we’re starting to find things,” he said, “but we haven’t had enough yet high-quality studies where we are able to put all the pieces together definitely.”
