The psychophysiological concomitants of craving: Peripheral and cognitive processing in smokers and non-smokers

Abstract

Substance abuse is prevalent worldwide and represents the largest preventable health problems worldwide. Craving has been identified as an undeniable symptom of substance abuse withdrawal and is also one of the most commonly reported reasons for relapse in those attempting to quit. However, little is actually known about the complex nature of the many components driving craving. While a significant increase in research on the role that craving plays in addiction and relapse has been conducted, consistency in the conceptualization and assessment of this complex phenomenon remains challenging. Most studies in the area do not address the multiply determined nature of craving. Thus, there is a clear need for additional research not only to gain a better understanding of craving, but to also develop a more reliable mode for indexing the multiple elements of craving simultaneously. The present study assessed the contingent negative variation (CNV) and baseline heart rate variability (HRV) in smokers and non-smokers while they viewed smoking, neutral and positive images. Participants (N= 50, 24 smokers) took part in a standard S1-S2 CNV paradigm which consisted of three blocks (40 trials each) of visual stimuli separated by six seconds. Baseline HRV (5 minutes) was assessed prior to any image presentations. Event-related potential (ERP) data were collected from frontal, central, and parietal sites along the vertex (FZ, FCZ, CZ, PZ). Results indicated smokers experienced increased feelings of craving following the smoking images compared to the neutral and positive images. Smokers’ CNV responses also differed during the smoking images, compared to the neutral and positive images. This relationship was found for the early CNV component at all electrode sites and for the total CNV component at FCZ, CZ, and PZ. Additionally, smokers’ early CNV responses also differed from non-smokers (observed in FCZ and CZ). Interestingly, there was also a relationship between HF-HRV and early CNV amplitude (observed at FZ and FCZ) independent of smoking status. At baseline, there was only one group difference, mean heart rate (HR), therefore, (as part of the multidimensional approach to understanding craving) after all classical CNV analyses were conducted, baseline mean HR was entered as a covariate and the analyses were performed again. MANCOVA results with baseline mean HR (a measure which is classically known to index physical activity) did not reflect any major change in the findings. Taken together it appears that CNV is capable of indexing craving in smokers and that increased HRV may provide an important benefit to smokers that allows them to avoid cognitive deficits that appear during cue related processing. Future research may want to consider matching smokers’ cognitive processing parameters to therapeutic techniques that target their individualized vulnerabilities.