Transcranial Direct Current Stimulation in Substance Use Disorders: A Systematic Review of Scientific Literature.

INTRODUCTION: New treatment options such as noninvasive brain stimulation have been recently explored in the field of substance use disorders (SUDs), including transcranial direct current stimulation (tDCS).

OBJECTIVES: In light of this, we have performed a review of the scientific literature to assess efficacy and technical and methodological issues resulting from applying tDCS to the field of SUDs.

METHODS: Our analysis highlighted the following selection criteria: clinical studies on tDCS and SUDs (alcohol, caffeine, cannabis, cocaine, heroin, methamphetamine, and nicotine). Study selection, data analysis, and reporting were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Exclusion criteria were as follows: clinical studies about tDCS among behavioral addiction; review and didactic articles; physiopathological studies; and case reports.

RESULTS: Eighteen scientific papers were selected out of 48 articles. Among these, 16 studied the efficacy of tDCS applied to the dorsolateral prefrontal cortex, and 8 suggested the efficacy of tDCS in reducing substance craving.

CONCLUSIONS: In light of these data, it is premature to conclude that tDCS over the dorsolateral prefrontal cortex is a very efficient technique in reducing craving. Small sample size, different stimulation protocols, and study duration were the main limitations. However, the efficacy of tDCS in treating SUDs requires further investigation.