Nicotine and cannabis activate similar areas of the brain that are associated with reinforcement and reward. Furthermore, co-use of the substances can lead to cross-sensitization, meaning nicotine can enhance the subjective effects of cannabis. In recent years, electronic cigarettes have started to replace tobacco cigarette use in the young adult population. This has led researchers to explore possible relationships between electronic cigarette use and cannabis use. There are many mechanisms linking e-cigarette and cannabis use. These include similar routes of administration, including the ability to use the substances simultaneously, and common liabilities from shared risk factors, such as sociodemographic status, familial substance use, genetics, and other environmental factors. Lastly use of nicotine may serve as a gateway to cannabis use and vice versa. This study examines the potential links between e-cigarette use in adolescence and cannabis use later in life in young adults from the United Kingdom.
The study’s sample consisted of 10,251 young adults who were part of the Millennium Cohort Study (MCS) within the UK. Participants completed confidential surveys assessing if they had used e-cigarette or vaping devices and frequency of use at ages 14 and 17. They were also asked at age 11, 14, and 17 if they had ever smoked a tobacco cigarette as well as frequency of use. Lastly, at ages 14 and 17 participants were asked about lifetime use as well of frequency of cannabis product use. Data was analyzed using logistic regression models to evaluate cannabis use at 17 in those who did and did not use electronic cigarettes at age 14.
Results of the data analysis found e-cigarette use by age 14 was associated with 4.2 higher odds of cannabis use by age 17. After controlling for tobacco cigarette use, cannabis use at age 17 was still 2.75 times higher in e-cigarette users. E-cigarette use was also associated with higher likelihood of frequent cannabis use at age 17. Alcohol use at an early age, low school engagement, and parental drug use were also associated with greater probability of cannabis use. Researchers also explored the inverse relationship to assess if cannabis use at age 14 was predictive of e-cigarette use at age 17. Their results showed that cannabis use by age 14 was not associated with later use of tobacco or electronic cigarettes.
Takeaway: E-cigarette use during early adolescence may provide predictive value in assessing likelihood of cannabis use later in young adulthood.