Daily marijuana smoking negatively affects teens

Sep 10, 2014, 1:58 PM EDT
Gabriela lights a marijuana joint in a cannabis club on August 22, 2014 in Barcelona, Spain.
David Ramos/Getty Images

Several studies conducted have led researchers to suggest that teenagers who smoke marijuana on a daily basis face adverse effects later in life that include mental problems, social issues, learning disabilities, and low motivation.

Reuters quotes some of the researchers on the studies:

"Our findings are particularly timely given that several U.S. states and countries in Latin America have made moves to decriminalise or legalise cannabis, raising the possibility the drug might become more accessible to young people," said Richard Mattick, a professor at Australia's National Drug and Alcohol Research Centre at the University of New South Wales, who co-led the study.
Using data from three large and long-running studies, the researchers found that people who smoke cannabis daily before the age of 17 are more than 60 percent less likely to complete high school or obtain a university degree.
The researchers combined individual-level data on up to 3765 young cannabis users from 3 large, long-running longitudinal studies from Australia and New Zealand to investigate the consequences of adolescent cannabis use on young adults.
They determined associations between the frequency of cannabis use before the age of 17 years (never, less than monthly, monthly or more, weekly or more, or daily) and 7 developmental outcomes, which were assessed up to the age of 30 (completing high school, obtaining a university degree, cannabis dependence, use of other illicit drugs, suicide attempt, depression, and welfare dependence).
In adjusted analyses, "clear and consistent" associations between the frequency of adolescent cannabis use and most young-adult outcomes investigated emerged, Dr. Silins said. There was also a clear dose-response relationship, with daily cannabis users showing the strongest effects.