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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Behavioral Impact of Prefrontal Anodal Transcranial Direct Current Stimulation on Smokers

Conditions
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Addiction, Smoking

Intervention / Treatment
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* Procedure: sham tDCS
* Procedure: active tDCS


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: sham tDCS<br>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 | Procedure: sham tDCS<br>* 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<br>|
| Active Comparator: active tDCS<br>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 | Procedure: active tDCS<br>* anodal tDCS applied over the right DLPFC 2mA, 20minutes, 10 sessions, 2 per day<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Smoking | Self-reported number of cigarettes smoked each day | Baseline (three days before starting tDCS regimen) to one-month after | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exhaled carbon monoxide | measured using a CO monitor (MicroCo, Milford, MA, USA). | Baseline, one-week (after the last tDCS session) and one-month later | 
| Craving | measured using a 5-item Likert-type scale questionnaire of smoking urge | For each of the 10 tDCS sessions: Baseline and 0 hour post-tDCS (immediately after) | 
| fMRI brain reactivity during a smoking cue-reactivity task | measured using an event-related fMRI paradigm | Baseline and one-week (after the last tDCS session) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tobacco, smoking, tDCS, DLPFC