Second, the enactment of medical marijuana laws could lead to a change in community attitudes on both medical and non-medical marijuana use, including reduced disapproval and perceived riskiness of use, which could subsequently influence marijuana use and abuse/dependence. Prior work has shown a relationship between formal behavioral sanctions and the subsequent creation of informal social norms and regulation of behavior (Scott, 2000). However, the scarce existing evidence on the link between marijuana laws, attitudes and marijuana use raises questions about the validity of this type of causal link. Khatapoush et al., for example, found that while perceived harm of marijuana decreased after legalization of medical marijuana in California, approval of recreational use and actual recreational use did not change with the change in the laws (Khatapoush and Hallfors, 2004).
