Does Anxiety Mediate the Relationship Between Cannabis Use and Psychotic-Like Experiences in Emerging Adults? Investigating a Conditional Process Model in a Multi-Site University Sample
Authors: Bernusky Haley , Tibbo Phil , Yunus Fakir , Conrod Patricia , Keough Matthew , Thompson Kara , Krank Marvin , Stewart Sherry 
Published: September 2022

Background/Aim: Cannabis is commonly used by Canadian emerging adults (ages 18-25 years), many of whom attend post-secondary institutions. Frequent cannabis use has been linked with psychotic-like experiences (PLEs); however, the exact nature of this complex relationship remains to be fully understood. Anxiety is a prevalent mental health concern in emerging adults and university students, and anxiety has been independently linked with both cannabis use and PLEs. Males and females use cannabis and experience mental health differently: females tend to be more anxious while males tend to use more cannabis and are at higher risk for psychotic-like experiences. In this first of two studies for my Masters, I evaluated whether anxiety mediated the relationship between cannabis use frequency and PLEs in emerging adult undergraduates. I then tested the impact of moderation by biological sex by assessing if the mediation model held statistical significance across sexes. Hypotheses: H1) Consuming cannabis more frequently will be associated with more anxiety which, in turn, will be associated with greater PLEs in emerging adults, H2) the anxiety mediation pathway will be statistically stronger for females; and H3) males will have a stronger direct association between cannabis use and PLEs. Method: A sample of 1,507 first- and second-year emerging adult university students (mean [SD] age = 19.2 [1.52] years; 67% female) were recruited. Cross-sectional, self-report survey data were collected throughout fall 2021 from five Canadian universities as part of the UniVenture substance misuse prevention trial. Validated measures capturing demographics, cannabis use frequency, anxiety, and PLEs were administered. Results: The mediation model with cannabis use frequency as the predictor, PLEs as the outcome, and anxiety as the mediator was tested, followed by testing a moderated mediation (conditional process) model with biological sex moderating the paths from cannabis use frequency to anxiety and from cannabis use frequency to PLEs using the PROCESS macro for SPSS. Bootstrapped 95% confidence intervals showed evidence of a significant indirect effect of cannabis use on PLEs through anxiety for emerging adults (a-path p < .001; b-path p < .001; 95% CI [.016, .048]), supporting H1. No direct effect was found (c’-path p = .946) suggesting that the relationship between frequent cannabis use and PLEs may be fully mediated by anxiety. In the second model, significant moderated mediation was found (95% CI [.005, .060]). More frequent cannabis use was associated with increased anxiety among females only. Conditional indirect effects showed significant mediation through anxiety for females (95% CI [.020, .056]), but not males (95% CI [-.015, .028]), consistent with H2. No significant sex moderation was found for conditional direct effects of cannabis on PLEs for either males (p = .667) or females (p = .907), contrary to H3. Conclusion: Assuming replication in prospective research, results highlight anxiety as an important intervention target in frequent female cannabis users to potentially prevent the development or worsening of PLEs. Understanding differential trajectories from frequent cannabis use to PLEs is important for informing individualized prevention and programming and encouraging health equity.