Marijuana and the 'Gateway Theory'

Experts agree that the use of marijuana is not causally linked to the use of other illicit substances

Sequentially, most consumers of illicit substances first experimented with either alcohol or tobacco

  • "Alcohol is the most commonly used substance, and the majority of polysubstance using respondents consumed alcohol prior to tobacco or marijuana initiation. Respondents initiating alcohol use in sixth grade reported significantly greater lifetime illicit substance use and more frequent illicit substance use than those initiating alcohol use in ninth grade or later. ... Our results ... assert that the earlier one initiates alcohol use, the more likely that they will engage in future illicit substance use." (Prioritizing alcohol prevention: Establishing alcohol as the gateway drug and linking age of first drink with illicit drug use, The Journal of School Health, 2016)

Statistically, the overwhelming majority of people to try marijuana do not go on to use other illicit drugs, and most typically cease their use of marijuana by middle age

In jurisdictions where marijuana is legally accessible, adults typically report decreasing their use of other controlled substances. In this sense, marijuana appears to act more as a potential ‘exit drug’ rather than as an alleged 'gateway'

  • "[F]indings on cannabis substitution effect and the biological mechanisms behind it strongly suggest that cannabis could play a role in reducing the public health impacts of prescription and non-prescription opioids. ... The growing body of research supporting the medical use of cannabis as an adjunct or substitute for opioids creates an evidence-based rationale for governments, health care providers, and academic researchers to consider the implementation and assessment of cannabis-based interventions in the opioid crisis." (Rationale for cannabis-based interventions in the opioid overdose crisis, Harm Reduction Journal, 2017)
  • "Among respondents that regularly used opioids, over three-quarters (76.7%) indicated that they reduced their use since they started medical cannabis. This was significantly ( p < 0.0001) greater than the patients that reduced their use of antidepressants (37.6%) or alcohol (42.0%). Approximately two-thirds of patients decreased their use of anti-anxiety (71.8%), migraine (66.7%), and sleep (65.2%) medications following medical cannabis." (Substitution of medical cannabis for pharmaceutical agents for pain, anxiety, and sleep, Journal of Psychopharmacology, 2017)

In clinical settings, marijuana use is associated with reduced cravings for cocaine and opiates

  • "In this longitudinal study, we observed that a period of self-reported intentional use of cannabis ... was associated with subsequent periods of reduced use of crack [cocaine]. ... Given the substantial global burden of morbidity and mortality attributable to crack cocaine use disorders alongside a lack of effective pharmacotherapies, we echo calls for rigorous experimental research on cannabinoids as a potential treatment for crack cocaine use disorders." (Intentional cannabis use to reduce crack cocaine in a Canadian setting: A longitudinal analysis, Addictive Behaviors, 2017)