Artificial Intelligence-Augmented Human Instruction and Surgical Simulation Performance: A Randomized Clinical Trial.

The gateway hypothesis posits that substance use initiation occurs in a sequential progression through different stages (; ), usually beginning with alcohol and tobacco, followed by cannabis, then illegal/illicit substances (; ; ; ). While some research suggests these associations hold even when adjusting for certain individual (e.g., socio-economic status, personality traits) and contextual factors (e.g., family functioning) (; ; ), other research indicates the gateway sequence of substance use may no longer hold when accounting for such factors. One factor potentially impacting order of initiation involves shifts in a country’s product market and use prevalence (). In the US in 2023, lifetime use rates of cigarettes, e-cigarettes, cigars, alcohol, and cannabis among young adults (ages 18-25) were 34.6%, 50.1%, 23.1%, 74.7%, and 50.0% respectively, and past-month rates were 10.6%, 24.1%, 5.3%, 49.6%, and 25.2% (). Because of the higher use rates for cannabis and e-cigarettes than cigarettes and cigars, the traditional gateway hypothesis may not hold. Furthermore, these associations may be impacted by cohort effects, as cannabis and e-cigarette use has increased in the past decade () coinciding with expansion of non-medical cannabis legalization () and e-cigarette popularity since 2010 (). Notably, cannabis legalization may increase cannabis use but reduce tobacco and alcohol use (; ). Despite these important societal changes, limited research has assessed the gateway effects of cigars or newer substances like e-cigarettes to cannabis. Some studies show effects for e-cigarettes (; ; ; ) and cigars (), while others show no or minimal effects or associations (e.g., e-cigarettes (), cigars ()). Furthermore, several studies show that some use cannabis before tobacco and/or alcohol or that cannabis use increases the probability of progressing to tobacco/alcohol use (; ; ; ; ; ; ; ; ; ).