PubMed Health: Busting the "Gateway Theory"

This summary was published by NORML: 

Vancouver, Canada: Cannabis use is associated with slower rates of injection initiation among at-risk youth, according to longitudinal data published in the journal Drug and Alcohol Review.

Canadian researchers assessed drug use progression in a cohort of 481 street-involved youth over a ten-year period.

Authors reported: "[W]e observed a high rate of injection initiation among at-risk street-involved youth. Our results indicate that periods of frequent cannabis use were associated with slower rates of initiation: daily cannabis use was associated with a 34 percent decrease in the hazard rate of injection initiation."

They concluded: "[F]requent cannabis use was negatively associated with injection initiation. ... Given the expansion of cannabis legalization throughout North America, it is encouraging that cannabis use was associated with slower time to initiation of injection drug use in this cohort. This finding challenges the view of cannabis as a gateway substance that precipitates the progression to using harder and more addictive drugs."

A 2017 study published by several of the same researchers previously reported that cannabis use was associated with reduced consumption of crack cocaine in a cohort of polydrug users.

For more information, contact Paul Armentano, NORML Deputy Director, at: paul@norml.org. Full text of the study, "Cannabis use is associated with lower rates of initiation of injection drug use among street-involved youth: A longitudinal analysis," appears in Drug and Alcohol Review.