First- versus second-generation electronic cigarettes: predictors of choice and effects on urge to smoke and withdrawal symptoms.

Aims: To (1) estimate predictors of first- versus second-generation electronic cigarette (e-cigarette) choice; and (2) determine whether a second-generation device was (i) superior for reducing urge to smoke and withdrawal symptoms (WS) and (ii) associated with enhanced positive subjective effects.

Design: Mixed-effects experimental design. Phase 1: reason for e-cigarette choice was assessed via questionnaire. Phase 2: participants were allocated randomly to first- or second-generation e-cigarette condition. Urge to smoke and WS were measured before and 10 minutes after taking 10 e-cigarette puffs.

Setting: University of East London, UK.

Participants: A total of 97 smokers (mean age 26; standard deviation 8.7; 54% female).

Measurements: Single-item urge to smoke scale to assess craving and the Mood and Physical Symptoms Scale (MPSS) to assess WS. Subjective effects included: satisfaction, hit, 'felt like smoking' and 'would use to stop smoking' (yes versus no response).

Findings: Equal numbers chose each device, but none of the predictor variables (gender, age, tobacco dependence, previous e-cigarette use) accounted for choice. Only baseline urge to smoke/WS predicted urge to smoke/WS 10 minutes after use (B =0.38; P <0.001 and B =0.53; P <0.001). E-cigarette device was not a significant predictor. Those using the second-generation device were more likely to report satisfaction and use in a quit attempt (χ(2)  = 12.10, P =0.001 and χ(2)  = 5.53, P =0.02).

Conclusions: First- and second-generation electronic cigarettes appear to be similarly effective in reducing urges to smoke during abstinence, but second-generation devices appear to be more satisfying to users.