How Should Transcranial Direct Current Stimulation be Used in Populations With Severe Alcohol Use Disorder? A Clinically Oriented Systematic Review.

Background and rationale. Severe alcohol use disorder (SAUD) is a major public health concern, given its massive individual, interpersonal, and societal consequences. The available prevention and treatment programs have proven limited effectiveness, as relapse rates are still high in this clinical population. Developing effective interventions reducing the appearance and persistence of SAUD thus constitutes an experimental and clinical priority. Among the new therapeutic approaches, there is a growing interest for noninvasive neuromodulation techniques, and particularly for transcranial direct current stimulation (tDCS) as an adjunctive treatment in neuropsychiatric disorders, including SAUD. Methods. We propose a systematic review, based on preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, evaluating the available evidence on the effectiveness of tDCS to improve clinical interventions in SAUD. Results. We provide an integrative overview of studies applying tDCS in clinical populations with SAUD, together with a standardized methodological quality assessment. We show that the currently available data remain inconsistent. Some data suggested that tDCS can (1) reduce craving, relapse or alcohol-cue reactivity and (2) improve cognitive control and inhibition. However, other studies did not observe any beneficial effect of tDCS in SAUD. Conclusions. Capitalizing on the identified strengths and shortcomings of available results, we present evidence-based clinical guidelines to integrate tDCS in current clinical settings and to combine it with neurocognitive training.