Teens under age 17 who use marijuana every day are 60 percent less likely to graduate from high school, compared with their peers who have never used the drug, a new study finds.

Teen marijuana users are 18 times more likely to become dependent on the drug, seven times more likely to attempt suicide, and eight times more likely to use other illicit drugs later in life, the researchers report in The Lancet Psychiatry.

The researchers analyzed date from three previous studies that included almost 4,000 participants, according to CNN. The teens in the study were followed until they were 30. The more frequently teens used marijuana, the greater the risks of the drug, the study found.

“The results provide very strong evidence for a more direct relationship between adolescence cannabis use and later harm,” said lead author Edmund Silins with the National Drug and Alcohol Research Centre at the University of New South Wales, Australia. “The findings are particularly timely given the growing movement to decriminalize or legalize cannabis because this has raised the possibility the drug might become more accessible to young people.”

“Our results provide strong evidence that the prevention or delay of cannabis use is likely to have broad health and social benefits,” Silins noted in a news release. “Efforts to reform cannabis legislation should be carefully assessed to ensure they reduce adolescent cannabis use and prevent potentially adverse effects on adolescent development.”

An estimated 6.5 percent of high school seniors use marijuana daily or almost daily, according to the 2013 Monitoring the Future survey. The annual study looks at behaviors and attitudes of teens in eighth, 10th and 12th grades.