Preliminary evidence for altered interoceptive processing in smokers.

BackgroundNeuroimaging evidence suggests that interoceptive processing might be altered in nicotine addiction, however this has not yet been confirmed with behavioral measures. Therefore, we investigated the perception of internal bodily states in smokers (49) and people who had never smoked (n=51), by measuring interoceptive sensitivity (IS) and interoceptive awareness (IA). MethodsIS was measured with a heartbeat tracking task and a heartbeat discrimination task. Performance on the heartbeat tracking task may be influenced by one's ability to estimate an elapsed time interval so this was controlled by a time-estimation (TE) task. IA was measured using two sub-scales from the Multidimensional Assessment of Interoceptive Awareness (MAIA). Participants in the addiction group completed the Revised Fagerstrom Test for Nicotine Dependence (FTND-R) to measure addiction severity. ResultsIndependent-samples t-tests revealed that non-smokers performed significantly better than smokers on the heartbeat tracking task (p = 0.007, d = 0.22). There were no group differences observed for the remaining variables. Furthermore, none of the variables predicted addiction severity. ConclusionsThis is the first demonstration of behavioral differences in interoception in participants with nicotine addiction. When considered in the context of previous research, these findings support the hypothesis that interoceptive processing may be disturbed in addiction. These data also support the hypothesis that behavioral and self-report measures of interoception assess two separate constructs.