In the US, federal law has greatly restricted our ability to study any medical properties of cannabis. But, given some limited studies and many anecdotal stories, a number of states have gone ahead and legalized medical marijuana. This has allowed some population-level studies of what is happening in states, but they have faced additional complications, such as laws that vary from state to state and the ongoing legislation of recreational drug use. the image.
Just how confusing all of this may be was driven home this week by the release of a book suggesting that one of medical marijuana’s biggest successes was a hoax. A couple of early studies show that states that have legalized the use of medical marijuana see reductions in opioid-related deaths. The new study replicated those results but found that trend has reversed in recent years, with those states seeing increased deaths. While the authors of the new study suggest that the initial results are null, others suggest that the changing legal landscape and changes in drug abuse may have driven the change.
What does everyone agree on?
Back in 2014, researchers compared to deaths due to opioid abuse in states with and without legalization of medical marijuana. For the decade before 2010, the trend was clear: states that allowed medical marijuana had lower rates of drug-abuse-related deaths.
While this is a correlation study that cannot be accepted in causal systems, it is not very difficult to find a possible explanation: one of the uses of medical marijuana has been the management of severe pain, the same thing that opioids are used to treat . Substituting marijuana for these pain medications provides a clear pattern that can explain the correlation. As later studies confirmed this trend, the search ended up being used in ongoing political debates about appropriate policies for marijuana use.
That set the stage for a new study, which uses data from previous work but increases its range to include the years up to and including 2017. Instead of 20% drop, the study found a 20%. increase in opioid abuse deaths in states that have legalized medical marijuana.
Beyond that, this may seem like another case of a famous study failing to replicate. In fact, the authors note that if they cut the data off in 2010, they were able to reproduce the results of the previous study. It’s just that, starting around 2005, the trend flattened out and then started to increase in size in 2012. The changes before 2010 were too short and mild to have much effect on the trend seen in the system. longer data; those after 2012 simply did not exist when the original study was conducted.
Therefore, everyone agrees that the original culture is real, and the analysis that reveals the most recent culture is scientific. Where people are separated is meaning.
A spurious connection?
So, what are the possibilities that can explain why a correlation will go away over time? The simplest explanation, and one that the new papers are arguing for, is that the correlation is meaningless in the first place. Things happened to line up for a short time but eventually diverged because they were unrelated in the beginning.
The book makes a number of arguments in favor of spurious connections. He noted that medical cannabis users make up only 2.5 percent of the general population, raising questions about whether they can have much of an impact on society-wide trends. But they also cut that argument to a degree by noting that a separate study of medical cannabis found that its users are more likely to both use and abuse prescription drugs. That suggests that medical cannabis has a better chance of influencing trends in specific populations at risk of opioid overdoses.
In the view of the authors of the paper, however, the association between medical marijuana use and pain abuse is inconsistent with the former limiting the latter. They added that there is no clear connection between the number of opioid overdose deaths and the strengthening of marijuana laws, which can range from stricter limits on the types of marijuana available for medicinal use to allowing recreational use. exercise. At the moment, however, these high-level policies have only been in place for short periods of time and in a limited number of states, so their separate analysis leads to considerable statistical uncertainty. As such, it is not really possible to say anything about the effects of policy stringency yet.
But what else have we learned?
To get an additional perspective on this issue, we spoke with one of the authors of the first paper describing the medical marijuana-opioid relationship. Chinazo Cunningham practices internal medicine, including addiction treatment, at the Albert Einstein College of Medicine and Montefiore Health System. He argues that the original reasons for thinking that convergence might be important are still valid and have been supported by additional data in the meantime. “Randomized clinical trials show that cannabis reduces pain in humans,” Cunningham told Ars. “And then we also have several studies that show that states with prescription drugs have reduced the prescription of opioids. We also know that patients report that they take less opioids for their pain when they use marijuana. .”
(While preparing this area, Another book has been released shows that medical marijuana laws are associated with fewer opioid prescriptions. But he found that recreational marijuana laws are not, and the effects are specific to those under 55.)
While these don’t necessarily mean that a match is indicative of a real connection, Cunningham suggests they are enough to make it worth considering. And, if there is a connection, this suggests that something must have changed to decouple the two.
Cunningham has two ideas about what might account for that change. One is a change in the cause of opioid overdose deaths. The increase in deaths from prescription opioids stopped around 2010, the point where the original study ended the data, and has been roughly flat since then. By contrast, deaths due to heroin began climbing dramatically at about the same time, and those have been followed by an even faster increase in deaths due to synthetic opioids such as fentanyl, which began in 2015. It is possible that the change is focus from prescription drugs. to illegal drugs, or the high potency of fentanyl, has changed the relationship with marijuana that should be used for medical purposes.
Another confounding effect that Cunningham noted is that there may be a change in the affected population due to states that have legalized medicinal cannabis since 2010. “We know that the states with the highest opioid overdose, Ohio, West Virginia, and Pennsylvania have all recently legalized medical cannabis,” he said. This is not to say that the original fit is clearly detailed; rather he suggests that the information should not be dismissed as useless without looking at these additional factors further.
But the possible causes Cunningham mentioned indicate that finding anything out will be difficult. “There are a lot of other things that are happening at the same time (changes in) medical cannabis policies are also happening,” he said. While researchers are trying to track the changes happening in drug abuse, the drugs of abuse are changing, the states that allow medical marijuana are changing, and the availability of cannabis is changing rapidly.
And Cunningham, like the authors of the new book, shows that all we can do now is in harmony with music. “We need to do studies that can determine the obstacle-research that has been assigned. And in order to do this, the federal government has to change the policy,” he told Ars, referring to the limits of a put to the research of marijuana. “Until that happens, we’re all going to be guessing, or it’s going to be a bit of a leap of faith while states continue to move forward. And really, that’s scary. Our policies should be guided by knowledge. -deep.”
PNAS2019. DOI: 10.1073/pnas.1903434116 (About DOIs).