As times continue to change, so does the world’s opinion on controversial substances like cannabis. Marijuana is being legalized in many places worldwide, policies which also include decriminalizing recreational use. As governments ease up on drug restrictions, one study suggests officials should also ease up on the age limit too. Researchers say dropping the age for marijuana use from 21 to 19 makes sense.

Researchers from the Memorial University of Newfoundland interviewed 20,000 individuals, who were at least 15 years-old, between 2004 and 2015. The study analyzed data from the Canadian Tobacco Use Monitoring Surveys (CTUMS) and Canadian Tobacco, Alcohol and Drugs Surveys (CTADS).

Individuals between the age of 19 and 20 who used cannabis were less likely to smoke cigarettes later in life. This differed from individuals who began their cannabis usage at age 18. The results didn’t reveal any significant findings for those who started using cannabis later in life. Based on this data, researchers say this is an indicator that the legal age for cannabis should be 19.

The report finds overall health was better for individuals who started usage at age 18. Mental health scores were also higher in individuals who started usage between 19 and 20, furthering the notion of a new minimum legal age.

“The lower level of completed education reported in those who first used cannabis at an earlier age may reflect poor neurological development or a higher ‘drop-out’ rate from further education,” lead author Dr. Nguyen says in a media release. “It is also possible that those who initiate cannabis use early may use it as a gateway for further illicit drug use, resulting in poorer health in later life, which may explain the poor general or mental health scores recorded in the study.”

Dr. Nguyen cautions there is no research to prove those possibilities at this time.

“Taking into account all measured outcomes, our results indicate that, contrary to the Canadian federal government’s recommendation of 18 and the medical community’s support for 21 or 25, 19 is the optimal minimum legal age for non-medical cannabis use,” Nguyen explains. “Keeping the legal age below 21 may strike a balance between potential increases in underground markets and illegal use, and avoiding the adverse outcomes associated with starting to use cannabis at an earlier age.”

Despite the research conducted, the lead author notes that these findings may not be as accurate as possible, considering the findings come from self-reporting by the individuals in the surveys.

The study was published in BMC Public Health.