A new systematic review published in the journal Addictive Behaviors challenges the longstanding claim that cannabis acts as a gateway drug to other substances.
Researchers from the University of Montreal, The University of Queensland, and McGill University conducted an extensive analysis of prospective studies to explore the relationship between the age of cannabis use onset and later substance use issues.
The review examined 16 studies published between 2000 and 2024, focusing on adolescents and controlling for individual, social, and substance-related factors. While an earlier age of cannabis use onset was linked to an increased risk of developing what some researchers call “cannabis use disorder”, the findings did not support the notion that cannabis use leads to significant problems with other substances, such as alcohol or harder drugs.
Researchers noted that the association between cannabis use and substance use disorder (SUD) for other drugs was inconsistent across studies, with no clear evidence to suggest that cannabis use directly increases the likelihood of abusing other substances. This undermines the decades-old “gateway drug” theory often cited by prohibition advocates to justify harsh anti-cannabis laws.
Although the study found that the gateway drug theory may have no basis in science, researchers did note that “Prevention approaches should aim to delay the onset and reduce the frequency of CU among youth to reduce risk of the development of CUD.”
For more information on this study, click here.
