Marijuana and the ‘Gateway Theory’


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

  • “This study is the first to use nationally representative data across all 50 states and the District of Columbia to comprehensively explore the broader impacts of RMLs [recreational marijuana laws], providing some of the first evidence on how marijuana legalization is affecting illicit drug use, heavy alcohol use, arrests for drug and non-drug offenses, and objectively-measured adverse drug-related events including drug-related overdose deaths and admissions into substance abuse treatment services. … [W]e find little compelling evidence to suggest that RMLs result in increases in illicit drug use, arrests for part I offenses, drug-involved overdoses, or drug-related treatment admissions for addiction.”
  • “Marijuana use has been proposed to serve as a ‘gateway’ that increases the likelihood that users will engage in subsequent use of harder and more harmful substances, known as the marijuana gateway hypothesis (MGH). The current study refines and extends the literature on the MGH by testing the hypothesis using rigorous quasi-experimental, propensity score-matching methodology in a nationally representative sample. … Results from this study indicate that marijuana use is not a reliable gateway cause of illicit drug use. As such, prohibition policies are unlikely to reduce illicit drug use.”
  • “There is compelling and enduring evidence that marijuana is not a gateway drug, … Yet, non-evidence-based political factors on both the left and the right remain the reason for the persistence of the gateway myth.”
  • “The psycho-social observation that the use of some psychoactive substances (‘drugs’) is often followed by the use of other and more problematic drugs has given rise to a cluster of so-called ‘gateway drug hypotheses,’ and such hypotheses have often played an important role in developing drug use policy. The current essay suggests that drug use policies that have drawn on versions of the hypothesis have involved an unjustified oversimplification of the dynamics of drug use, reflecting the interests of certain stakeholders rather than wise social policy. The hypothesis should be retired.”

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

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.”
  • “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.”

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