Where medical marijuana is legal, illegal use climbs | Reuters

Researchers found that illegal use of marijuana and rates of cannabis use disorder rose to a greater extent in U.S. states that adopted laws legalizing marijuana for medical purposes than in states that didn’t adopt such laws.

The risks of medical marijuana laws are important to convey, said lead author Deborah Hasin, of Columbia University’s Mailman School of Public Health in New York.

“Just as the case for alcohol, not everybody who uses it is harmed but there are some risks,” Hasin told Reuters Health.

Previous research that focused on adolescents’ use of the drug in the wake of medical marijuana laws didn’t find an increase in that age group, she said.

“The laws may not be too relevant and salient to teenagers so we thought it was important to look at adults,” said Hasin.

The new conclusions, published in JAMA Psychiatry, are drawn from three national studies conducted between 1991 and 2013. The studies compared illicit drug use in the past year and rates of cannabis use disorder between…