Effects of emotional arousal on amygdala neural response and cigarette craving reduction during repeated exposure to graphic warning labels

Graphic warning labels (GWLs) have been implemented on cigarette packaging worldwide. In the U.S., GWLs have encountered legal obstacles based on the tobacco industry arguments that their aversive imagery unnecessarily triggers strong emotional arousal. This longitudinal study evaluated the effect of the high-arousal GWLs on cigarette craving and the neural substrates of emotional processing. 158 adult smokers were exposed to either high-arousal (n=79) or low-arousal (n=79) GWLs that were attached to their own cigarette packs for 4 weeks. Craving and brain activity in response to GWLs and control stimuli were measured using functional magnetic resonance imaging before and after the 4-week exposure. The amygdala, which plays a key role in emotional processing, served as the a priori region of interest. Results indicate that, at baseline, high-arousal GWLs elicited a larger reduction in craving and stronger amygdala neural response compared to low-arousal GWLs; however, at week 4, GWL-induced craving reduction and amygdala response became comparable between the high-arousal and low-arousal groups. Amygdala response mediated GWLs effects on craving reduction, which was moderated by arousal and time in such a way that the amygdalas mediating role was more pronounced for high-arousal than low-arousal GWLs at baseline but did not differ between groups at week 4. Together, the results suggest that the impact of emotional arousal on cigarette cravings decreases over time, potentially due to the amygdalas diminishing responsivity to repeated presentations of high-arousal imagery. Low-arousal GWLs may represent a more feasible approach for tobacco control efforts in the U.S.