Effect of smoking status on neuronal responses to graphic cigarette warning labels

Background Smoking is responsible for a large proportion of cancer, respiratory and cardiovascular deaths. Nevertheless the health risks of smoking are still underestimated in many smokers. The present study aimed to examine neurobiological responses to graphical warnings on cigarette packings in non-smokers and patients with tobacco dependence. Methods Twenty non-smokers and twenty-four patients with tobacco dependence participated in a functional MRI study during that pictures of different categories were presented ((a) EU-warning pictures, (b) text-only warnings, (c) neutral pictures with short information). Patients contributed twice in the experiment (after 10 hours nicotine withdrawal / about 5 minutes after nicotine consumption). Results Smokers during withdrawal demonstrated increased neuronal responses predominantly in subcortical, temporal and frontal brain regions that are associated with emotional and cognitive processes during the presentation of graphical warnings compared to neutral pictures. In smokers after smoking and non-smokers, the differences between graphical warnings and neutral pictures were increased compared to smokers during withdrawal. The comparison of the graphical warnings with text-only labels demonstrated the importance of affective brain regions especially in smokers after smoking and in non-smokers. During withdrawal, the neural responses associated with graphical warnings and text-only labels differed only marginally. Discussion and conclusion The results suggest that emotional and cognitive reactions to graphical warnings are predominantly seen in smokers after smoking and in non-smokers. The impact of these pictures during withdrawal seems to be less pronounced;in this case, more unspecific processes seem to be important, including the projection of sensory signals to the cerebral cortex.