Transcranial Direct Current Stimulation in Addiction

In the field of drug addiction, despite the enormous efforts to find effective medications, there are only a handful of approved pharmacological treatments, with limited efficacy. Neuromodulation techniques, such as transcranial direct current stimulation (tDCS), could target different neural circuits implicated in drug addiction, such as the Dorso-Lateral-Prefrontal-Cortex (DLPFC) and its interaction with other subcortical areas. A recent review reported that tDCS stimulation over DLPFC was effective for craving reduction in different clinical trials, showing some level of evidence. TDCS showed higher evidence in Alcohol-, Tobacco- and Cocaine-Use Disorders, whereas Gambling Disorder and the area of binge eating represent addictive behaviours with possible and promising developments. As regards to the region of stimulation, positive results on craving were substantially equivalent both with ‘anodal right DLPFC/cathodal left DLPFC’ compared with ‘anodal left DLPFC/cathodal right DLPFC’. Serious side effects have rarely been observed, also in this typology of patients, with mild erythema or itching sensation under the electrodes as the most reported symptoms. Although there is no report of epileptic seizures in these patients in association with the use of tDCS, a conservative approach needs to be proposed, avoiding the stimulation procedures in conditions of intoxication or withdrawal. Strong limitations concerning the study design, the small sample size, the high level of heterogeneity of protocols, the lack of studies with long follow-up periods, and the doubts regarding tDCS dose, electrode montage and placement indicate the need for further studies with double-blind design.