[Transcranial direct current stimulation (tDCS) in adults with attention deficit hyperactivity disorder. A systematic review].

Introduction: The prevalence of attention deficit hyperactivity disorder (ADHD) in the population is currently 4%. It is usually associated with problems related to executive functions, attention and emotional regulation. Non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS), may compensate for cognitive impairment, thereby benefiting neuroplasticity and long-term outcomes.

Aim: The aim is to find evidence concerning the dual application of tDCS with cognitive stimulation activities in the treatment of ADHD in adults, in relation to attention, executive functions and emotional regulation.

Materials And Methods: Two reviewers conducted a literature search of Web of Science and PubMed on 22.02.2023, and selected articles that included ADHD patients aged 17-65 years old. The results were analysed using synthesis without meta-analysis (SWiM).

Results: Seven of 956 articles were selected for the present review, and were all related to executive functions and attention. No article related to neuromodulation of emotional regulation in adults with ADHD was found. Significant results related to attention and executive functions, and specifically inhibitory control, were found. All studies followed the international 10-20 system developed for the electroencephalogram.

Conclusions: Further research is required in view of the limited number of studies found on the symptomatological treatment of ADHD with tDCS in adult populations and the lack of awareness of emotional regulation. This research should use a treatment involving more than two sessions. These tasks do not involve learning and involve a stimulation of more than 1.5 mA.