FRIDAY, May 18, 2018 (HealthDay News) -- Boys who start smoking pot before they are 15 years old are more likely to have a drug problem when they're adults than those who don't start until they are a few years older.
That's the assessment of new research from the University of Montreal.
For the study, researchers led by doctoral student Charlie Rioux examined data on 1,030 boys included in a long-running project that began in the early 1980s. On a yearly basis, boys aged 13 to 17 were asked if they had ever smoked pot.
Then, when they were 20 years old and again eight years later, those same study participants were asked again about their pot use or if they had used any other drugs, including cocaine, hallucinogens, amphetamines, barbiturates, tranquilizers, heroin and inhalants.
The earlier the boys started smoking pot, the more likely they were to have a problem with drugs later on in life, the study authors said. And the boys who started at a young age were at higher risk regardless of how often they used the drug.
"The odds of developing any drug abuse symptoms by age 28 were nonsignificant if cannabis use had its onset at ages 15 to 17, but were significant and almost doubled each year if onset was before age 15," the study authors wrote.
The findings indicated that boys who started smoking marijuana as soon as they reached adolescence had a 68 percent risk of developing a drug abuse problem by the time they were 28. In comparison, the risk was 44 percent among boys who didn't use the drug until they are 15 or older.
The study findings were published recently in the Canadian Journal of Psychiatry.
"The odds of developing any drug abuse symptoms by age 28 were reduced by 31 percent for each year of delayed onset of cannabis use in adolescence," the researchers reported.
In addition, the investigators noted a link between bad behavior and drug use. The earlier boys were involved in delinquent behaviors -- such as stealing, vandalizing property, drinking alcohol or getting into fights -- the earlier they started smoking pot and the higher their risk for a drug problem down the road.
The findings underscore the importance of teaching elementary school-aged children early on about the risks associated with smoking pot, particularly since the drug is much stronger than it was decades ago, the researchers said.
While the study found an association between earlier marijuana use and later drug abuse, it did not prove a cause-and-effect relationship.
Still, the fact that public acceptance of the drug is growing as more U.S. states move to legalize it makes educating kids about the risks even more critical, the team concluded.
"It may be important to implement these programs by the end of elementary school to prevent early onset of cannabis use," Rioux said in a university news release.
"Since peer influence and delinquency were identified as early risk factors for earlier cannabis onset and adult drug abuse, targeting these risk factors in prevention programs may be important, especially since prevention strategies working on the motivators of substance use have been shown to be effective," Rioux explained.
The U.S. National Institute on Drug Abuse has more about marijuana.