Attentional bias in smokers and e-cigarette users who formerly or currently smoke cigarettes: an eye-tracking study

Rationale Dual use of tobacco cigarettes and e-cigarettes has become increasingly common, yet little is known about how e-cigarette use influences behavioural features underlying smoking, such as attentional bias (AB). Objectives We aimed to examine the influence of e-cigarette use on AB towards smoking-related cues among current and former cigarette smokers using eye-tracking technology. Methods Participants included 62 cigarette smokers, 67 e-cigarette users (41 dual users, 26 full-switchers), 61 former cigarette smokers and 65 non-using controls. AB was assessed using a free-viewing eye-tracking task consisting of 85 slides, each displaying 4 images. Test images contained smoking-related cues. The primary outcome was relative fixation time (RFT; milliseconds). AB was calculated by subtracting mean RFT to neutral images from mean RFT to smoking-related images. Results Cigarette smokers, dual users and full-switchers exhibited significantly greater AB towards smoking-related cues than former smokers and non-using controls (p ≤ 0.004). Former smokers showed AB comparable to non-using controls (p = 0.998). The association between baseline smoking craving and AB differed significantly between cigarette smokers and dual users, with smoking craving more strongly associated with AB among cigarette smokers than dual users. In contrast, baseline vaping craving was not reliably associated with AB towards smoking-related cues in either dual users or full-switchers. Conclusions Smoking-related cues retain their incentive salience among e-cigarette users who currently smoke and those who transitioned to fully e-cigarettes. Complete nicotine abstinence reduced the salience of smoking cues to levels comparable to non-using controls, suggesting partial or full reversal of neuroadaptations underlying smoking cue salience.