The theory of the gateway effect appeared in the 1970s in order to describe the potential proximity between licit and illicit drug consumption. Firstly descriptive, this theory was rapidly used in order to produce predictive models, in particular linking cannabis consumption to that of heroin .
Today, the gateway theory applied to vaping products argues that vaping could initiate young non-smokers into smokers.
This assumption is used in particular to justify the restrictive regulation of vaping products in many countries as indicated, for example, by the EU Tobacco Products Directive, or TPD .
For vaping, the gateway effect is based on two assumptions:
- A number of young non-smokers are initiated into vaping.
- Vaping by young non-smokers leads them to smoking.
Is there really a gateway effect between vaping and starting to smoke?
L’existence d’un effet passerelle entre vapotage et tabagisme est très difficile à étudier expérimentalement. Il est, en effet, méthodologiquement imThe existence of a gateway effect between vaping and smoking is very difficult to study experimentally. It is methodologically impossible to establish a causal link between these two practices. This is because too great a variety of factors can lead to smoking  such as for example the fact of having smoker friends or parents.
These “methods locks” maintain fuzziness on the existence of an actual gateway between vaping and smoking such that the hypothesis cannot be verified or rebutted.
Is the gateway effect rebutted by field observations?
While it is experimentally difficult to prove or rebut this theory, it appears contradictory with factual observations made on the population:
- In countries where vaping is widespread, a significant drop in smoking among adolescents is observed.
- In countries which impose restrictions limiting the use of vaping products, adolescent smoking continues to increase .
The gateway effect hypothesis implies the fact that an adolescent decides to vape which leads them to becoming a smoker while in the absence of vaping, they would never have smoked. Thus, the gateway effect should increase the smoking prevalence of adolescents in countries where vaping is widespread since without vaping, these adolescents would never have become smokers.
For the same reasons, in countries where vaping is not widespread, adolescent smoking should not increase more rapidly than in countries where vaping is implanted.
In France, according to the survey ESCAPAD 2017, 1.9% of young people aged 17 vape on a daily basis: more than half of them say they also smoke on a daily basis. Among adolescents who have tried both products, the majority have already tried ordinary cigarettes before e‑cigarettes .
Finally, in general, it is observed that very few non-smokers are vapers. Take for example the United Kingdom, which is currently the country most liberal and most favourable to vaping.
It could be thought that this political position of vape promotion as a tool for smoking cessation favours the use of personnel vaporisers by non-smokers. In fact, a UK government report of 2018  on the prevalence of smoking in Great Britain shows that only 4.2% of vapers were not smokers, i.e. 0.5% of the adult population. Among these 4.2% of vapers, nearly half do not consume nicotine.
Similarly, Pr. Dautzenberg, in 2017, presented a summary of the findings on the use of vaping products by adolescents in Paris, in Great Britain and in the USA . In these countries where vaping is strongly implanted, it appears that:
- Smoking is in clear decline.
- Among non-smokers having tried vaping, very few become vapers on a daily basis.
- The use of nicotine-free e-liquids is growing.
Quite recently, a study on the prevalence of smoking and the use of vaping products among North American adolescents is providing new light on the question . It is based on data from the “National Youth Tobacco Survey” (NYTS) produced between 1999 and 2018.
In particular the researchers find that:
- The smoking of American adolescents decreased between 1999 and 2018 while the use of vaping products has increased since their introduction in 2009.
- The age of initiation to smoking has increased since 2014 while that of vaping has remained stable.
- Vaping is not associated with an increase of nicotine consumption by American adolescents and is removing young people away from tobacco cigarettes.
- Young vapers are initiated into nicotine consumption later than young smokers which implies reduced risks.
Thus, while the existence of a gateway effect between vaping and smoking is a relevant concern, the actual findings do not provide any proof of its existence. On the contrary, they show rather that vaping comes “into competition” with smoking and tends to replace it in countries which permit it.
While this information is accessible to the general public, many international and government institutions use the hypothesis of a gateway effect to justify or recommend repressive measures as regards vaping products maintaining smoking in the populations they are supposed to protect.
- Vanyukov, M. M., Tarter, R. E., Kirillova, G. P., Kirisci, L., Reynolds, M. D., Kreek, M. J., … & Neale, M. C. (2012). Common liability to addiction and “gateway hypothesis”: theoretical, empirical and evolutionary perspective. Drug and alcohol dependence, 123, S3-S17.
- European Union (EU). Directive 2014/40/EU of the European Parliament and of the council of 3 April 2014 on the approximation of the laws, regulations and administrative provisions of the member states concerning the manufacture, presentation and sale of tobacco and related products and repealing Directive 2001/37/EC. Off J Eur Union 2014 L 127
- Etter, J. F. (2018). Gateway effects and electronic cigarettes. Addiction, 113(10), 1776-1783.
- Foxon, F., & Selya, A. S. (2020). Electronic Cigarettes, Nicotine Use Trends, and Use Initiation Ages among US Adolescents from 1999–2018. Addiction.
- Spilka S, Le Nézet O, Janssen E, Brissot A, Philippon A, Shah J, et al. Les drogues à 17 ans : analyse de l’enquête ESCAPAD 2017. Tendances. 2018;(123) :1‑8