The comparative efficacy of first- versus second-generation electronic cigarettes in reducing symptoms of nicotine withdrawal

Addiction. 2015 May;110(5):862-7. doi: 10.1111/add.12870. Epub 2015 Mar 5.


Background and aims: Currently, electronic cigarettes (e-cigarettes) are studied as though they are a homogeneous category. However, there are several noteworthy differences in the products that fall under this name, including potential differences in the efficacy of these products as smoking cessation aids. The current study examined the comparative efficacy of first- and second-generation e-cigarettes in reducing nicotine withdrawal symptoms in a sample of current smokers with little or no experience of using e-cigarettes.

Design: Twenty-two mildly to moderately nicotine-dependent individuals were randomized to a cross-over design in which they used first- and second-generation e-cigarettes on separate days with assessment of withdrawal symptoms directly prior to and after product use.

Setting and participants: A community-based sample recruited in the Midwest region of the United States reported a mean age of 28.6 [standard deviation (SD) = 12.9]. The majority were male (56.5%), Caucasian (91.3%), reported smoking an average of 15.2 (SD = 9.6) tobacco cigarettes per day, and a mean baseline carbon monoxide (CO) level of 18.7 parts per million (p.p.m.).

Measurements: Symptoms of withdrawal from nicotine were measured via the Mood and Physical Symptoms Scale.

Findings: Analysis of changes in withdrawal symptoms revealed a significant time × product interaction F(1, 21) = 5.057, P = 0.036, n(2) P = 0.202. Participants experienced a larger reduction in symptoms of nicotine withdrawal after using second-generation compared with first-generation e-cigarettes.

Conclusions: Second-generation e-cigarettes seem to be more effective in reducing symptoms of nicotine withdrawal than do first-generation e-cigarettes.

Keywords: Comparative efficacy; electronic cigarettes; ends; nicotine; smoking; withdrawal symptoms.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Analysis of Variance
  • Cross-Over Studies
  • Electronic Nicotine Delivery Systems / instrumentation
  • Electronic Nicotine Delivery Systems / methods
  • Electronic Nicotine Delivery Systems / statistics & numerical data*
  • Female
  • Humans
  • Male
  • Nicotine / adverse effects*
  • Smoking Cessation / methods*
  • Smoking Cessation / statistics & numerical data
  • Substance Withdrawal Syndrome / prevention & control*
  • Tobacco Use Disorder / therapy*
  • Treatment Outcome


  • Nicotine