What is the Impact of Marijuana Legalization? Testing for Differences in Marijuana Cognitions as a Function of Marijuana Policies Open Access
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Background: Over the past decade the US has seen significant shifts in marijuana policy with some states having no marijuana legalization (NML), some passing medical marijuana laws (MML) and others passing recreational marijuana laws (RML). Previous literature, which has focused almost exclusively on adolescents or young adults, suggests that legislation impacts marijuana cognitions. One gap in the literature is an absence of research testing whether there are differences in perceived norms and attitudes associated with marijuana among adults as a function of legislation. The Prototype Willingness Model (PWM) and Theory of Planned Behavior (TPB) are two dominant models that explain decisions to use substances. These models posit that attitudes and perceived social norms have an indirect impact on behavior, marking these as important cognitions to study in the context of marijuana. Objectives: The present study tested whether (1) injunctive norms, (2) descriptive norms and (3) attitudes, differ as a function of the legal status of marijuana. Methods: Sample matching was used to recruit a nationally representative sample of US adults (N=3150; 41.1% female; 57.5% White). Participants' state of residence was classified as NML, MML, or RML. Analysis of Covariance (ANCOVA) tested whether attitudes and norms (i.e., injunctive and descriptive) differed as a function of state after controlling for age, gender, and ideology. Results: Objective 1. Those in RML states reported higher injunctive norms (M = 3.78; SE = .06) than those in MML states (M = 3.25; SE = .04) and NML states (M = 2.91; SE = .05; F = 71.33, p < .01). The difference between MML and NML states was also statistically significant. Objective 2. Those RML states reported higher descriptive norms (M = 47.92; SE = 1.03) than those in MML states (M = 45.07; SE = .66) and NML (M = 44.18; SE = .82); F = 4.22, p < .05). The difference between MML and NML states was not statistically significant. Objective 3. There were no significant differences in attitudes in RML states (M = 3.21; SE = .06) compared to MML (M = 3.07, SE = .04) and NML (M = 3.03; SE = .05; F = 2.66, p > .05). Conclusions: Results suggest that among US adults, legislation has the potential to influence norms, but may not have an impact on attitudes.