Lack of startle modulation by smoking cues in smokers

Rationale. The startle reflex methodology has been used to study the effects of nicotine in humans and the motivational effects of smoking cues in smokers. However, no other studies investigate startle modulation by smoking cues in smokers compared to non-smokers. In the other studies, smoking deprivation was manipulated in smokers or smokers were not compared directly to non-smokers. Objective. The goal of this study was to examine the temporal course of information processing following the presentation of a smoking-related cue using the startle probe methodology in smokers compared to non-smokers. Methods. Thirty-four smokers were selected on the basis of nicotinic dependence according to the DSM-IV, and compared to 34 non-smokers. During testing, subjects viewed neutral pictures and smoking related pictures displayed on a computer screen. Acoustic startle stimuli were delivered at various times after picture onset (60, 120 or 5000 ms) to examine inhibition by lead stimulus and the affective modulation of startle. Results. The magnitude of startle reflex inhibition increased in smokers compared to non-smokers, at 60 and 120 ms. In all, there was no PicturexGroup interaction effect. Conclusion. We showed that smoking cues have no impact on the startle reflex of either group, even if, in line with previous results, prepulse inhibition was higher in smokers than non-smokers. These results suggest that smoking cues have no effect on the positive reinforcement of nicotine consumption, and that cognitive factors play a primary role in the development and maintenance of tobacco dependence.