Anodal Transcranial Direct Current Stimulation (tDCS) in the Treatment of Tobacco Addiction

The aim of this study is to determine whether a powerful technique of noninvasive brain stimulation, transcranial direct current stimulation (tDCS), could reduce cigarette smoking and constitute a treatment of tobacco addiction.

Tobacco is estimated to cause more than 5 millions yearly deaths in the developed world. Although most smokers would like to quit, relapse rates remain high. It seems that this relapse is linked with the process of craving, which is a powerful desire to smoke elicited by smoking deprivation or exposure to situations or cues that are associated with smoking. Neuroimaging studies have shown that the dorsolateral prefrontal cortex (DLPFC), and especially the right part, is critically involved in processing the craving of smoking. Increasing the activity of the DLPFC by noninvasive brain stimulation has been demonstrated to be effective in decreasing craving symptoms in cigarette smokers. The aim of this study is to determine whether a powerful technique of noninvasive brain stimulation, transcranial direct current stimulation (tDCS), could reduce cigarette smoking. tDCS is a painless and safe brain stimulation method capable of modulating cortical excitability. The nature of these modulations depends on stimulation polarity: anodal tDCS is thought to cause neuronal depolarisation and thus enhancing cortical excitability whereas cathodal stimulation is proposed to reduce excitability. The investigators hypothesize that anodal tDCS applied repetitively to the right DLPFC could constitute a treatment of tobacco addiction. Therefore, the investigators will conduct a sham-tDCS-controlled, randomized, double-blind study.

sham transcranial direct current stimulation The anode (7 x 5 cm) is placed on the right dorsolateral prefrontal cortex. A large cathode (10 x 10cm) is placed on the left occipital region

active anodal tDCS over the right dorsolateral prefrontal cortex The anode (7 x 5 cm) is placed on the right dorsolateral prefrontal cortex. A large cathode (10 x 10cm) is placed on the left occipital region Intensity of the stimulation: 2 mA Duration of the stimulation: 20 min 10 sessions, 2 per day

sham condition as delivered by the stimulator "study mode" (2mA during 40s and brief current pulses until the end of the stimulation) 20 minutes, 10 sessions, 2 per day

Inclusion Criteria: Age from 18 to 55 years old Tobacco consumption from 10 to 25 cigarettes, for at least 1 year Strong tobacco dependence at the Fagerstrom Test (score >= 5) Motivation to quit with a score >=12 at the Motivation to Quit Smoking Scale (Q-MAT) Informed consent Exclusion Criteria: Concomitant Axe I psychiatric disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM IV) Other addictive disorder (DSM IV) No history of smoking cessation drug the previous year Psychotropic treatment Pregnancy or nursing