The Effect of Different tDCS Protocols on Drug Craving and Cognitive Functions in Methamphetamine Addicts

Background and objective: Drug craving is considered to be a major problem in addiction treatment. Neuroimaging research has revealed various areas for drug craving, among which two key areas are the dorsolateral prefrontal cortex (DLPFC) and the cerebellum. The DLPFC is involved in different cognitive tasks like the inhibitory control over seductive options harboring the promise of immediate reward. The cerebellum considered to be related to cognition and memory and gets activated by drug-related cues. Therefore based on the previous researches we decided to study the effects of applying tDCS on six different protocols in reducing Drug Craving and increasing Cognitive Functions in Methamphetamine Addicts. Methods: The present study is a semi-experimental, with pre/post-test, and a control group. Based on a simple sampling method, 15 male methamphetamine addicts in two rehabilitation centers in Tehran were recruited. The participants were 18-65 years old with a minimum 12-month history of methamphetamine dependence. Visual Analog Scale (VAS), The Go/No-Go Task and The N-Back Task was administered before and after single session of tDCS. tDCS applied on six protocols which were: 1. The right DLPFC anodal and the left DLPFC cathodal stimulation 2. The right DLPFC cathodal and the left DLPFC anodal stimulation 3. The right DLPFC anodal and the right arm cathodal stimulation 4. The left DLPFC anodal and the left arm cathodal stimulation 5. The right cerebellar hemisphere (O2) anodal and the left cerebellar hemisphere (O1) cathodal stimulation 6. The right cerebellar hemisphere (O2) cathodal and the left cerebellar hemisphere (O1) anodal stimulation. The data were analyzed by covariance method using SPSS-22 software Results: Study results indicated while single session tDCS effects on craving were not significant, it increased cognitive inhibition especially in protocol 2: The right DLPFC cathodal and the left DLPFC anodal stimulation Conclusion and discussion: Single session of tDCS has an insignificant effect on craving but it can increase cognitive inhibition significantly. These findings extend the results of previous studies on the effects of brain stimulation for drug craving reduction in other drug type settings.