Introduction: Transcranial direct current stimulation (tDCS) has recently been raising interest in its therapeutic impact on tobacco use disorder. This study investigates the effects of repeated frontal tDCS (anode: F3, cathode: F4) on cigarette consumption, craving and executive functions.
Material and methods: In a randomized sham-controlled trial, 24 individuals received active (2.0 mA) and 20 individuals received sham stimulation (0.3 mA) for 20 min on five consecutive days. The participants indicated their tobacco cravings, answered questionnaires and completed neuropsychological tasks at various time points throughout the study. Carbon monoxide (CO) levels and the daily numbers of consumed cigarettes were recorded.
Results: Both intervention groups experienced a significant decrease in the daily number of smoked cigarettes, CO levels, and craving after the stimulation, however, there were no improvements in executive functions. These results did not differ significantly between both intervention groups. Additionally, in the active group, a higher level of perceived stress and a lower level of self-control were linked to a lower cigarette consumption, respectively a higher reduction of the level of CO.
Conclusion: This study does not support the hypotheses that tDCS reduces cigarette consumption, attenuates substance craving, or improves executive functions beyond the placebo effect. Our subgroup analysis suggests that high levels of perceived stress and low self-control may be predictors for a successful reduction in cigarette consumption. Furthermore, the placebo effect might be rather high for light smokers, whereas heavy smokers seem to benefit more from the specific effects of tDCS.
Clinical trial registration number: NCT03691805.
Keywords: Craving; Dorsolateral prefrontal cortex; Executive functions; Tobacco use disorder; Transcranial direct current stimulation.
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