Abstract
Background: Precursors of marijuana use in early adolescence are largely unknown because studies generally focus on marijuana use among older adolescents or adults.
Methods: In this study, we examined precursors of marijuana use in a sample of 1023 Dutch early adolescents (aged 11-14 at Time 1) who were never-marijuana user at baseline, by applying a 3-wave longitudinal design. The theory of planned behavior (TPB) was used as a theoretical framework and posits that marijuana-specific cognitions (i.e., positive and negative expectancies, evaluative attitude, social approval, and self-efficacy) are antecedents of marijuana use and that this relationship is mediated by the intention to start using marijuana.
Results: In accordance with these premises, our results indicated that evaluative attitude, social approval, and self-efficacy at Time 1 are related to marijuana use at Time 3 (20 months follow-up) via the intention to start using marijuana at Time 2 (8 months follow-up). More specifically, the structural equation models showed that more positive marijuana attitudes, more approval from the social environment, and lower self-efficacy were related to marijuana use initiation through a stronger intention to start using marijuana.
Conclusion: This outcome is important for prevention efforts in that our results underline the importance of weakening adolescents' positive attitudes toward marijuana, decrease social approval of marijuana use, and stimulating the development of early adolescents' refusal skills with respect to marijuana use.
