A new study from the University of Montreal shows that when cannabis use is started before the age of 15 the likelihood of developing dependency and abuse problems are 68% by the age of 28. This likelihood is reduced by almost one third for each year cannabis use is deferred.

The researchers examined data collected on 1030 boys by the Montreal Longitudinal and Experimental Study between 1991 and 1995. What they found was that the younger the boys were when they began to use cannabis, the more likely they were to have drug abuse issues later on in life

But, the study says, it's worth noting that adult cannabis use is not linked to the same sorts of drug abuse issues, and in most cases can be safely consumed by adults.

"The odds of developing any drug abuse symptoms by age 28 were non-significant 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 says.

Additionally, the researchers found that the more often cannabis is used in adolescence, the chance of developing drug abuse symptoms rises as well.

These findings are not dissimilar to what is known about alcohol consumption, says the study's author, Charlie Rioux. He hopes these findings will lead to early drug education, and says children should be educated on substance abuse from a young age with a focus on health and avoiding peer pressure.