More News:

June 17, 2015

Study: medical marijuana laws don't influence teens to smoke

Researchers tracked marijuana use among U.S. teens between 1991-2014

Marijuana Teens
Marijuana file art/for PhillyVoice


With medical marijuana laws now on the books in 23 states, opponents fear that teenagers will increasingly interpret legalization as permission to light up. A new study from British medical journal, The Lancet Psychiatry, suggests otherwise, however.

Between 1991 and 2014, more than one million teens in 21 states with medical marijuana laws were asked whether they had smoked pot in the previous 30 days. Students in eighth, 10th, and 12th grades were included in the research, which covered 400 schools per year and found that while teen marijuana use was more prevalent in states that legalized medicinal use for the sick, there was no significant change corresponding with the passage of such laws in those states.

Our findings, consistent with previous evidence, suggest that passage of state medical marijuana laws does not increase adolescent use of marijuana. However, overall, adolescent use is higher in states that never passed such a law than in other states. State-level risk factors other than medical marijuana laws could contribute to both marijuana use and the passage of medical marijuana laws, and such factors warrant investigation.

The study, funded by the US National Institute on Drug Abuse, Columbia University Mailman School of Public Health and New York State Psychiatric Institute, sought to determine whether the passage of medical marijuana laws conveyed a message of acceptability or an absence of harmful health consequences.

Citing evidence of an increased likelihood of adverse effects such as short-term impairments in memory, coordination and judgment, as well as longer-term risks of altered brain development and cognitive impairments, the researchers suggest that resources should no longer be focused on the role of medical marijuana laws in adolescent use, but should instead be applied to identifying state-level and large-scale societal factors that do affect risk.

"In states working to legalize medical marijuana, this could give thoughtful legislators comfort in passing these laws," said Roseanne Scotti, director of the New Jersey chapter of the Drug Policy Alliance, in a report on the study by

Based on the questionnaire provided to students over the 24-year period of the study, 15.87 percent of students in the combined grade levels reported marijuana use in the past 30 days in states that had passed a medical marijuana law by 2014, compared to 13.27 percent of students in states that did not pass a similar law by 2014.

Last month, Pennsylvania Governor Tom Wolf came out in support of decriminalizing marijuana, pointing to overcrowded prisons and barriers to employment as harmful consequences of the state's stringent legal status on marijuana. Wolf also expressed support for allowing doctors to prescribe medical marijuana, however, a bill recently passed by the state's Republican-controlled Senate has faced opposition in the House of Representatives.