Most Anti-Marijuana Arguments Based on Opinion Not Science, Report Finds

A slew of anti-marijuana arguments just went up in smoke, according to one group of researchers.

Researchers from the International Centre for Science in Drug Policy (ICSDP) studied some of the more common anti-marijuana arguments and discovered that most of them are scientifically unfounded. The researchers worked to shed some light on the subject to stop the misguided information from negatively influencing public opinion, and in turn national policy.

“Many scientists are increasingly frustrated by the disregard of scientific evidence on cannabis use and regulation,” said the ICSDP in their recent report “State of the Evidence: Cannabis Use and Regulation.”

ICSDP researchers tackled 13 common claims surrounding cannabis use and regulation. They listed the arguments, then provided their assessment on the strength of the supporting evidence. Finally, they gave the “bottom line.”

“The claim that cannabis is a ‘gateway’ drug, for example, confuses correlation and causation,” said Dr. Carl Hart, a professor in psychology and psychiatry at Columbia University who sits on the scientific board of ICSDP. “Worse still is the fact that a false claim like ‘cannabis is as addictive as heroin’ is reported as front page news.”

According to Hart, there is no scientific evidence to date that suggests marijuana use leads to “harder” drugs, but there is scientific evidence that shows less than one in 10 lifelong marijuana users are addicted to the drug, compared to one in four for heroin users.

Furthermore, Hart believes the propagation of misinformation surrounding marijuana will change public perception for the worse and spur harmful policy.

“We are at a critical juncture, as more and more jurisdictions are reconsidering their policies on cannabis,” said Dr. Dan Werb, ICSDP director and co-author of the report. “Yet, the public discourse around cannabis is filled with frequently repeated claims that are simply not supported by the scientific evidence. Given that policy decisions are influenced by public opinion and media reports, there is a serious danger that misrepresenting the evidence on cannabis will lead to ineffective or harmful policy.”