Despite fears that relaxing marijuana control laws will lead to higher rates of pot use among youngsters, new research shows that less US teenagers are currently dabbling in weed than in 2002. Furthermore, the study – which appears in the Journal of the American Academy of Child and Adolescent Psychiatry – indicates that use of the drug is now less strongly associated with “conduct problems” such as fighting and stealing among adolescents.

To conduct their research, the study authors from the Washington University School of Medicine obtained data from the National Survey on Drug Use and Health in order to determine how rates of marijuana use and mental health disorders fluctuated among 12- to 17-year-olds between 2002 and 2013. During this period, 13 US states introduced medical marijuana programs, while a further 10 relaxed their restrictions on recreational cannabis smoking.

Though the proportion of youngsters with marijuana use disorders – such as dependence on the drug – remained more or less constant across this period, the researchers noted a 24 percent decrease in the number of teenagers exhibiting both marijuana use disorders and conduct problems. In other words, the correlation between weed dependence and behavioral issues fell by roughly a quarter.

Furthermore, the number of youths using cannabis in the US was 10 percent lower in 2013 than it had been in 2002, suggesting that the legal changes brought in during this time did not encourage more young people to smoke weed.

Exactly what has brought about this improvement is difficult to pinpoint, although the study authors suggest that it could have something to do with wider societal efforts to protect the mental health of children and curb adolescent delinquency. For example, the researchers cite “more frequent diagnosis and treatment of childhood behavior disorders, a rise in school-based programs to prevent violence and bullying, and the emergence of state antibullying laws” as possible contributors.

Commenting on these findings, study co-author Richard Grucza explained that “we don't know how legalization is affecting young marijuana users, but it could be that many kids with behavioral problems are more likely to get treatment earlier in childhood, making them less likely to turn to pot during adolescence. But whatever is happening with these behavioral issues, it seems to be outweighing any effects of marijuana decriminalization.”