The legalisation of marijuana leads to “more widespread use and many more health implications”, a new paper published in the New England Journal of Medicine has argued.

The review, penned by scientists from the National Institute on Drug Abuse (NIDA), links the drug to several significant adverse health effects including addiction, with nine percent of those who first experiment with the drug likely to become dependant on it.

And according to the co-author of the study, US drug tsar Dr Nora Volkow, director of the US National Institute on Drug Abuse, legalising marijuana will bring with it the same adverse health effects as alcohol and tobacco.

The study found that those intoxicated by cannabis are three to seven times more likely to cause a car crash than someone sober, risks that are compounded when the drug is mixed with alcohol.

The review, which outlines “the current state of the science related to the adverse health effects of the recreational use of marijuana”, also indicates the drug can reduce teens’ IQ, and 25 to 50 percent of daily users will develop dependency symptoms that meet the criteria for substance addiction.

It found that 6.5 percent of 12th graders report daily or near-daily marijuana use, with 60 percent of users believing regular marijuana use is not harmful.

The authors note that older studies incorporated into the review are based on the effects of marijuana containing lower THC — the main psychoactive chemical found in marijuana — and that stronger adverse health effects may occur with today’s more potent marijuana.

The research, the paper argued. also suggested that marijuana impairs critical thinking and memory functions during use, and that these deficits persist for days after using.