Study Suggests 19 is Good Legal Age for Marijuana Use; Some Experts Disagree

A new Canadian study suggests 19 is the optimal minimum age for legal recreational marijuana use. Some experts told Healthline they are concerned about the impact of the drug on brain development before 25.

The study found people who first used marijuana at age 18 were more likely to smoke cigarettes later in life than those who first used the drug at 19 or 20. Starting marijuana use at age 19 or higher was also linked with higher educational completion rates, and better physical and mental health. Outcomes were not improved when people started marijuana use at age 20 or later.

Linda Richter, PhD, Director of Policy Research and Analysis at Center on Addiction, disagreed with the study’s conclusions. She said her center’s research indicates that people ages 20 and under who use marijuana are about twice as likely as those who are 21 and older to meet the clinical criteria for marijuana use disorders. The risk remains elevated through age 25.

“The argument to reduce the legal age of sale of marijuana to 19 is misguided in much the same way similar calls to reduce the legal age of sale of alcohol or tobacco have been,” Richter said. “Although it is not realistic in our current legal, political and cultural climate, scientific research largely suggests that the optimal age of legalization to protect the public health would be 25 or later, not 19 or younger.”