Background: American Indian (AI) adolescents report high rates of marijuana use and related consequences and availability of marijuana has a robust relationship with marijuana use. The purpose of the present study was to examine the role of perceptions of approval (i.e., injunctive norms), and acceptability (i.e., descriptive norms and perceived harm) in the relationship between marijuana availability and marijuana use.
Methods: Data collected from 2009 to 2013 included 3498 AI 7th-12th graders residing on or near a reservation (47.8 % female). Multilevel mediation analyses were conducted using the MLmed macro in IBM SPSS v26.0 to account for the nesting of data within schools.
Results: The associations between marijuana availability and perceived risks (b=-.38, p < .001), descriptive norms (b = .80, p < .001), and injunctive norms related to marijuana use (b=-.24, p < .001), were significant. The associations between perceived risks (b=-.27, p < .001), descriptive norms (b = .14, p < .001), and injunctive norms (b=-.18, p < .001) and marijuana use were also significant. The indirect effects of marijuana availability on marijuana use through the pathways of perceived risks (b = .10, p < .001, 95 %CI[.08, .12]), descriptive norms (b = .11, p < .001, 95 %CI[.09, .14]), and injunctive norms related to marijuana use (b = .04, p < .001, 95 %CI[.03, .06]) were significant. The direct effect linking marijuana availability to marijuana use remained significant (b = .28, p < .001) but decreased by 37.8 %. when controlling for perceived risks, descriptive norms, and injunctive norms related to marijuana use.
Conclusions: Interventions aiming to reduce AI adolescent marijuana use should focus on availability and may also be well served by targeting descriptive and injunctive norms, as well as perceived risks of marijuana use.
Keywords: Adolescent; American Indian; Descriptive norms; Injunctive norms; Marijuana use; Perceived risks; Substance availability.
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