Legalizing Marijuana Doesn’t Increase Stimulant Prescriptions—And May Even Lower Rates, Study Finds

Legalizing marijuana for adults does not appear to be a contributor to what authors of a newly published study call the “substantial increases” in Schedule II stimulant use across the country in recent years. In fact, there’s even a possibility that cannabis legalization reduces stimulant use through a substitution effect, the paper says.

Researchers said the finding that ending marijuana prohibition isn’t linked to rising stimulant rates was contrary to what they expected when undertaking the project. The team predicted that legalizing recreational cannabis (RC) would lead to increases in stimulant use but found no evidence for that effect.

“The slopes over time for amphetamine, methyphenidate, and lisdexamfetamine, and the sum of all three stimulants illustrated no significant increase in stimulant distribution rates post-legalization,” the new research says, referring to stimulants commonly used to treat attention deficit hyperactivity disorder (ADHD). “This demonstrates that the legalization of RC has not played a crucial role in prescribed Schedule II stimulants.”

Between 2006 and 2016, the distribution of Schedule II stimulants nearly doubled, noted the research team at Geisinger Commonwealth School of Medicine, in Scranton, Pennsylvania. The stimulants are now the third most distributed class of prescription drugs in the country, with dispensing rates rising steadily from 2004 to 2019.

Cannabis “legalization did not contribute to a more pronounced rise in Schedule II stimulant distribution in states.”

Earlier research suggested that medical marijuana legalization did not impact stimulant distribution, authors wrote, but that report didn’t examine the possible impact of broader recreational legalization.

“The simplest explanation for our findings is that, at a population level, medical cannabis program legalization did not contribute to states experiencing quicker increases in schedule II stimulant distribution rates,” co-author Luke Cavanaugh said an interview with MedicalResearch.com about the prior research.

Going in to the analysis, researchers said they expected to see adult-use legalization lead to a rise in stimulant distribution. Recent research, they wrote, “has begun to elucidate the relationships between cannabis use and ADHD,” with notable crossover between people with ADHD and substance use disorder, specifically around marijuana. “Additionally,” the study adds, “research has shown that cannabis can cause neurocognitive deficiencies, including attention and memory problems, which are also seen in patients [with] ADHD.”

“Given that RC legalization would be expected to lead to increase cannabis use and, therefore, an increase in the number of people experiencing the neurocognitive symptoms that resemble ADHD, we expected that rates of prescription of the schedule II stimulants used to treat ADHD would increase after the legalization,” authors wrote.

In fact, results showed decreases in the rates of stimulant distribution after legalization, although those reductions weren’t statistically significant. That could suggest a substitution effect, authors wrote, in which people with ADHD self-medicate with cannabis rather than using stimulants.

“Based on the nonsignificant decrease in stimulant prescription seen in RC+ states post-legalization, some could make a case that legalization of RC increased accessibility, resulting in more people using cannabis to self-medicate their ADHD symptoms,” the study says. “Consequently, since some studies illustrate the positive effects of cannabis on the symptomology of patients with ADHD, the nonsignificant decrease in stimulant prescriptions could be the result of self-medicating with cannabis”

That takeaway, it adds, would be “consistent with a previously hypothesized substitution effect in which individuals might decide on using cannabis over prescription stimulants due to its perceived safety or preferred effects, leading to a reduction in stimulant distribution.”

There’s nevertheless “limited controlled scientific literature delineating the effects of cannabis on ADHD symptoms to be confident about the long-term effects that cannabis has on ADHD symptoms,” authors noted. “Additionally, although there was a decrease in distribution rates of RC + states post-legalization, it was not significant, making it difficult to conclude the impact that RC legalization had upon the decline in prescribed scheduled II stimulants for patients with ADHD.”

It’s also possible the results can be attributed to yet-undetermined factors, and the report says further research is necessary to better understand the relationship between cannabis and ADHD. One possibility, authors floated, is “that the emergence of legal cannabis could have disrupted the illicit drug market, potentially diminishing demand for prescription stimulants.”

Recreational cannabis legalization “is an ongoing policy discussion,” they added, “so it would be interesting to follow how the patterns observed in this study remain the same or change as more states legalize RC.”

While cannabis is often labeled a gateway drug by critics, a number of studies show that marijuana may in fact be acting more as a substitute for certain drugs, at least among some subsets of users.

A survey released by the American Psychiatric Association (APA) and Morning Consult last year found that Americans consider marijuana to be significantly less dangerous than cigarettes, alcohol and opioids—and they say cannabis is less addictive than each of those substances, as well as technology. A separate Gallup survey also found that Americans consider marijuana to be less harmful than alcohol, cigarettes, vapes and other tobacco products.

As for alcohol, a study published last November found that marijuana legalization may be linked to a “substitution effect,” with young adults in California “significantly” reducing their use of alcohol and cigarettes after the cannabis reform was enacted.

Recent research out of Canada also found a link between marijuana legalization and declines in beer sales, suggesting a substitution effect where consumers shift from one product to the other.

Other studies have linked cannabis legalization with reductions in the use of both prescription and nonprescription opioids. A report published last November, for example, linked legalizing medical marijuana with a “lower frequency” of nonprescribed pharmaceutical opioid use.

Last August, a federally funded study found that marijuana was significantly associated with reduced opioid cravings for people using them without a prescription, suggesting that expanding access to legal cannabis could provide more people with a safer substitute.

A separate study last year found that legal access to CBD products led to significant reductions in opioid prescriptions, with state-level drops of between 6.6 percent and 8.1 percent fewer prescriptions.

Another linked medical marijuana use to lower pain levels and reduced dependence on opioids and other prescription medications, while yet another, published by the American Medical Association (AMA), found that chronic pain patients who received medical marijuana for longer than a month saw significant reductions in prescribed opioids.

AMA also released research showing that about one in three chronic pain patients report using cannabis as a treatment option, and most of that group has used cannabis as a substitute for other pain medications, including opioids.

State-level marijuana legalization is associated with major reductions in prescribing of the opioid codeine specifically, too, according to a study that leveraged data from the federal Drug Enforcement Administration (DEA).

A 2022 study similarly found that giving people legal access to medical cannabis can help patients reduce their use of opioid painkillers, or cease use altogether, without compromising quality of life.

There’s also no deficit of anecdotal reports, data-based studies and observational analyses that have signaled that some people use cannabis as an alternative to traditional pharmaceutical drugs like opioid-based painkillers and sleep medications.

Marijuana Helps People Reduce Opioid Use And Manage Withdrawal Symptoms, New Federally Funded Study Finds

Photo courtesy of Chris Wallis // Side Pocket Images.