Before stimulation procedures onset, participants will undergo a clinical interview. All subject candidates will give written informed consent to take part in the study. Thereafter, they will be tested for their baseline pretreatment level of nicotine addiction in a screening meeting. This includes a report on the level of consumption (number of cigarettes smoked per day and overall duration in years) and a visual analog scale (VAS, see below for details). In addition, a urine sample for cotinine levels (nicotine metabolite) will be obtained in order to objectively measure levels of nicotine. In addition, several self-administered questionnaires will be given to the subjects in order to measure their baseline craving and nicotine dependence: