CU Boulder researchers studied cannabis-psilocybin co-users and cannabis-only users to look for similarities and differences between the two groups, including drug use motivations

In November 2022, Colorado voters approved Proposition 122, decriminalizing the personal use of mushrooms containing psilocybin, a psychedelic substance. That followed a decision by Colorado voters in 2014 to legalize recreational marijuana use.

Cannabis and psilocybin are becoming more commonly used, but there is still relatively little research on what happens when people use both, says Maddie Stanger, a University of Colorado Boulder Department of Psychology and Neuroscience researcher whose area of focus is motivations behind substance abuse and how people use substances to cope.

A recently published research paper co-authored by Stanger examined differences in cannabis dependence and reasons for using among individuals who regularly use marijuana and psilocybin versus marijuana-only users. In this case, co-use could either be the simultaneous use of cannabis and psilocybin or concurrent use over the same time period, Stanger explains.

Maddie Stanger is a CU Boulder Department of Psychology and Neuroscience researcher whose focus is motivations behind substance abuse and how people use substances to cope.

Stanger says this research is valuable because assessing individuals’ reasons for using substances can provide insight into potential harms, such as addiction or mental health issues. This is because motivations are related to quantity and frequency of use.

The researchers used a previous, larger study by the Center of Health and Neuroscience, Genes and Environment within the Department of Psychology and Neuroscience that investigated the effects of different cannabis strains on metabolic processes and insulin sensitivity.

From that study, researchers drew a test sample that included 97 regular cannabis users (those who used marijuana more than seven times a month) in Colorado. About a third of those had used psilocybin in the past three months while the rest had not. The researchers compared these two groups to understand how psilocybin use might affect marijuana use motives and dependencies.

Study participants were, on average, about 35 years old, mostly male and white, healthy overall and predominantly from the Boulder area, with at least some higher education. They reported using cannabis 21.73 out of the previous 30 days.

The motivations of all participants were measured using the Comprehensive Marijuana Motives Questionnaire (CMMQ), which encompasses 12 possible motives, including enjoyment, coping, experiment, boredom, celebration, altered perception, social anxiety, sleep and availability. Participants were also assessed for cannabis dependence based upon an 11-item Marijuana Dependence Scale (MDS) scoring system, which asks users to self-evaluate if they believe their cannabis use is excessive.

Considering motivation

Stanger says she and her research colleagues hypothesized that recent psilocybin users would have higher MDS scores and more strongly endorse coping, expansion (also referred to as “altered perception”) and enhancement/enjoyment motives compared with non-recent psilocybin users. Additionally, the researchers hypothesized that there would be correlations between dependence and coping motives for both groups, but that these would be stronger for recent psilocybin users relative to non-recent users.

The prediction that recent psilocybin users would have higher dependence scores than non-recent users was borne out, Stanger says. As expected, the research data demonstrated that psilocybin users showed mild signs of marijuana dependence, while non-psilocybin users did not, she says.

Additionally, compared to cannabis-only users, Stanger says the psilocybin co-user group exhibited higher scores on the motivations of enjoyment, boredom relief and availability/access, which can be indicative of dependency problems.

“Interestingly, we found that recent psilocybin users had indicated they were more likely to use for enjoyment, boredom and availability—and boredom and availability are shown in previous literature to be linked to increased cannabis problems and mental health symptoms,” she says.

However, contrary to the researchers’ hypothesis, Stanger says there was no difference in coping motives between the two groups.

The researchers note that these findings should be considered within the confines of the study limitations. Specifically, Stanger explains that the data came from a preexisting study and that this  analysis was not the primary purpose of the larger project. Thus, there is no data on the dose of the psilocybin used and no information as to whether cannabis and psilocybin were used simultaneously versus concurrently. Additionally, the study ideally would have involved a more diverse group of participants, Stanger adds.

Still, Stanger says she believes the research is timely and valuable, as more states have followed Colorado since 2014 in legalizing marijuana sales for medicinal or recreational purposes, and it’s conceivable that states will follow the Centennial State in legalizing psilocybin in the coming years.

In addition to Stanger, co-authors of this paper include Professor Angela Bryan and Research Assistant Professor Carillon Skrzynski, both with the Department of Psychology and Neuroscience; and Researcher Harmony Soffer with the University of Colorado Anschutz Medical Center. 

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