Abstract: | Compared to individual‐level research on religion and marijuana use, much less research has been conducted to investigate how the overall religious context of a geographic location may influence marijuana use during adolescence and early adulthood. Using multilevel analyses on two waves of the National Study of Youth and Religion (NSYR) merged with county‐level variables from the U.S. Census and the Religious Congregations and Membership Study (RCMS), this study finds that a county's higher Catholic population share is negatively associated with underage marijuana use frequency even after controlling for a wide range of individual and county‐level variables. Besides being robust, the Catholic contextual effect on marijuana use is also diffusive, influencing both Catholic and non‐Catholic youth who live in the same county. This study highlights the importance of viewing religious influence on substance use as a contextual, cultural force across different kinds of religious moral communities. |