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Background: Recent studies reported that transcranial direct current stimulation (tDCS) applied over the dorsolateral prefrontal cortex (DLPFC) reduced craving and cigarette smoking. We aimed to evaluate whether 3 sessions of tDCS over the DLPFC modulate cigarette smoking which is a critical factor in tobacco smokers. Methods: In a double-blinded, sham-controlled, parallel experimental study, 22 participants who wished to quit smoking received tDCS with the cathodal over the right DLPFC and anodal over the left DLPFC based on the 10–20 EEG international system (F4, F3) at an intensity of 1.5 mA for 20 minutes during three consecutive days. For sham stimulation, the electrodes placement was the same as for the active stimulation. Results: For the short time interval (8 days after the end of the tDCS regimen), the number of smoked cigarettes was reduced similarly in the active and sham groups (p < 0.001). Also, at the long time-interval (4 months after the end of the tDCS regimen) as compared to pre-tDCS, there was no significant difference in the number of smoked cigarettes in the active (p = 0.806) or the sham (p = 0.573) groups. Overall, there were no statistically significant differences between the active and sham tDCS groups on cigarette smoking. Conclusion: These findings suggested that 3 sessions of tDCS over the right and left DLPFC may reduce number of smoked cigarettes for short-time period but might not be significantly more effective than sham to decrease cigarette smoking. [ABSTRACT FROM AUTHOR]

Highlights • tDCS over the dorsolateral prefrontal cortex (DLPFC) has been shown enhance cognitive function. • Main finding was a significant improved of cognitive received active and sham stimulation. • This finding emphasizes the importance of double-blind placebo-controlled experiments in brain stimulation studies. Abstract Transcranial direct current stimulation (tDCS) is a neuromodulation tool that is used widely in many medical/experimental trials. We aim to assess the effect of tDCS over the dorsolateral prefrontal cortex (DLPFC) on cognitive function and obtain safety data in tobacco smokers. In this double-blinded experiment, 22 human subjects (male) were randomized into two groups: active (n = 12), and sham (n = 10) during three consecutive days for 20 min of continuous active versus sham stimulation each day. The cognitive functions outcome variables were the response time (attention switching task [AST]), and the percentage of correct answers (pattern recognition memory [PRM]). Safety data and visual analog scale were obtained before and after each tDCS session. After stimulation, AST showed significant improvement in mean correct latency, congruent and incongruent conditions for active group (p-value = 0.003, 0.004, and 0.005), and sham (p-value = 0.003, 0.004, and 0.003) respectively. In all 66 stimulations, mild itching was observed in 25.6% of cases and burning sensation was observed in 15.9% of cases, in both active and sham groups. While we predicted that performance would only increase during real stimulation, we observed an improvement in performance regardless of whether real or sham stimulation was used. tDCS appeared to be safe, well tolerated, and adhered to the international standard of safety in local population. [ABSTRACT FROM AUTHOR]