Withdrawal Symptoms From E-Cigarette abstinence among Former Smokers: a Pre-Post Clinical Trial.

Introduction:
This text summarizes the results of a clinical trial investigating the withdrawal symptoms experienced by former smokers who use e-cigarettes daily, when they abstain from using e-cigarettes for a week. The study found that abstinence from e-cigarettes caused withdrawal symptoms, and this appears to be a true withdrawal effect. The study has implications for basic science, clinical practice, and regulation.

Key Points:

* The study used a within-participants design, measuring withdrawal symptoms at multiple timepoints during each condition to test for a withdrawal time pattern.
* The study found that abstinence from e-cigarettes caused withdrawal symptoms, and this appears to be a true withdrawal effect.
* The magnitude of withdrawal in the study appears to be about 25% less than that for tobacco cigarette withdrawal, replicating results from cross-sectional surveys.
* One-third of participants met DSM-5 criteria for withdrawal, and one-quarter reported additional difficulty functioning during abstinence.
* The study did not find a significant correlation between the initial severity of e-cigarette withdrawal and relapse to e-cigarette use.
* The study had several limitations, including the lack of blindness, the absence of a concurrent comparison group of tobacco cigarette abstinence, and the lack of diversity in the sample.
* The study had several strengths, including the within-participants design, measures at multiple timepoints during each condition, methods to obtain a high rate of abstinence, use of a validated withdrawal scale, inclusion of measures of the functional significance of withdrawal effects, and inclusion of newly proposed withdrawal symptoms.

Main Message:
The study shows that e-cigarettes maintain physical dependence in former smokers. This is important for basic science, clinical practice, and regulation. The clinical significance of the findings is unclear, but the difference in withdrawal severity between e-cigarette and tobacco cigarette withdrawal appears to be small. The study suggests that dependence on e-cigarettes can be substantial, and treatments to help daily e-cigarette users stop need to be developed. The negative effects of withdrawal and the resultant increased risk of addiction and difficulty in stopping e-cigarettes would need to be factored into any risk vs. benefit assessment of e-cigarettes. The fact that abrupt cessation can cause withdrawal should be communicated to potential and current e-cigarette users.

hughes JR, Peters EN, Callas PW, et al. Withdrawal Symptoms From E-Cigarette abstinence among Former Smokers: a Pre-Post Clinical Trial. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2020;22(5):734-739. doi:10.1093/ntr/ntz129