Will Legalizing Marijuana Exacerbate America’s Opioid Epidemic?

White House Press Secretary Sean Spicer suggested that the Trump administration will likely enforce federal marijuana prohibition, citing America’s opioid crisis as a reason to do so — a claim that is inconsistent with available scientific data.

by Alex Kasprak

On 23 February 2017, White House Press Secretary Sean Spicer, in response to a question about the Trump Administration’s policy regarding states that have legalized marijuana in defiance of federal law, suggested that there would likely be greater enforcement of recreational cannabis in coming years.

To defend this claim, he cited America’s opioid addiction crisis as a reason the government should not “encourage” people to do drugs:

There’s a big difference between [medical] and recreational marijuana. And I think that when you see something like the opioid addiction crisis blossoming in so many states around this country, the last thing we should be doing is encouraging people. There’s still a federal law that we need to abide by when it comes to recreational marijuana and other drugs of that nature.

Implicit in this statement is the claim that recreational marijuana will lead individuals to other, harder drugs, in this case a class of prescription painkillers called opioids that are closely related to heroin.

That the United States is suffering through a serious crisis with opioid addiction and overdose is well accepted by the federal government.

From the Centers for Disease Control and Prevention:

Drug overdose deaths and opioid-involved deaths continue to increase in the United States. The majority of drug overdose deaths (more than six out of ten) involve an opioid.  Since 1999, the number of overdose deaths involving opioids (including prescription opioids and heroin) quadrupled. From 2000 to 2015 more than half a million people died from drug overdoses. 91 Americans die every day from an opioid overdose.

We now know that overdoses from prescription opioids are a driving factor in the 15-year increase in opioid overdose deaths. Since 1999, the amount of prescription opioids sold in the U.S. nearly quadrupled, yet there has not been an overall change in the amount of pain that Americans report. Deaths from prescription opioids — drugs like oxycodone, hydrocodone, and methadone — have more than quadrupled since 1999.

While these drugs can be both addictive and deadly in their own right, numerous studies have demonstrated an association between non-medical (i.e. recreational) prescription drug use and illicit drug use such as heroin, which has similar chemical properties to opioids:

From 2002–2013, past month heroin use, past year heroin use, and heroin addiction have all increased among 18-25 year olds. The number of people who started to use heroin in the past year is also trending up. Among new heroin users, approximately three out of four report abusing prescription opioids prior to using heroin.

The cause of this epidemic is not controversial — researchers almost universally attribute it to legal prescriptions from medical doctors that are either used by a patient legally, or illicitly diverted from a doctor to another individual. A 2016 review in the New England Journal of Medicine is unequivocal on this point:

Two major facts can no longer be questioned. First, opioid analgesics are widely diverted and improperly used, and the widespread use of the drugs has resulted in a national epidemic of opioid overdose deaths and addictions. More than a third (37%) of the 44,000 drug-overdose deaths that were reported in 2013 (the most recent year for which estimates are available) were attributable to pharmaceutical opioids; heroin accounted for an additional 19%. At the same time, there has been a parallel increase in the rate of opioid addiction, affecting approximately 2.5 million adults in 2014. Second, the major source of diverted opioids is physician prescriptions.

The increase in opioid painkillers prescriptions stems, most argue, from an increased demand for better pain medication in the early 1990s, a campaign that misrepresented their danger, and heavy marketing and drug development by pharmaceutical companies. Liberalization of cannabis policy, one will note, is not mentioned as a driving force behind the opioid crisis.

Perhaps just as pernicious as the falsehood implicit in Spicer’s press conference regarding the potential link between cannabis and opioids is his omission (or ignorance) of the fact that studies increasingly suggest that cannabis legalization results in a reduction of opioid overdoses.

The most exhaustive study on this topic, published in JAMA Internal Medicine in October 2014, analyzed the cause of death data from all states between 1999 and 2010, including states that had legalized medical marijuana during that period. These researchers found that states with medical marijuana programs had fewer opioid related deaths, and that these decreases happened in concert with marijuana reform:

States with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws. Examination of the association between medical cannabis laws and opioid analgesic overdose mortality in each year after implementation of the law showed that such laws were associated with a lower rate of overdose mortality that generally strengthened over time.

The data predates the legalization of recreational marijuana in any state, and therefore cannot test the relationship to full legalization — a distinction that Spicer did make in the press conference. It is unclear, however, if this distinction holds any relevance to the opioid epidemic. In January 2017, the National Academies of Sciences, Engineering and Medicine released a comprehensive review of academic studies concerning cannabis use published since 1999. Importantly, they found no individual study or credible meta-review linking cannabis use to increased opioid use.

While the concept of marijuana as a “gateway drug” remains controversial, there is a near-universal agreement that the opioid crisis was caused by an influx of legal prescription painkillers and is thus unrelated to marijuana use.

Spicer A) would be therefore hard-pressed to find evidence to support his implied connection between recreational cannabis and opioid addiction, and B) would have to find a way to get around an increasing number of studies suggesting that less strict marijuana laws result in fewer opioid deaths.

However, as noted in the the National Academies of Sciences review, the recent adoption of recreational marijuana laws and therefore the dearth of high quality studies make it impossible (at this time) to fully reject a connection between recreational pot and opioid addiction. In this respect, we rate the claim as Unproven.