THE EFFECT OF TRANSCRANIAL DIRECT CURRENT STIMULATION (TDCS) ON COGNITIVE FUNCTIONING IN INDIVIDUALS WITH ATTENTION DEFICIT/ HYPERACTIVITY DISORDER (ADHD)

Objective: Attention deficit/hyperactivity disorder (ADHD) is among the most prevalent neurodevelopmental disorders in children, often persisting into adulthood. It is characterized by two symptom domains: impulsivity and inattention, both associated with underlying neural and cognitive deficiencies. This study is the first to investigate the potential effects of transcranial direct current stimulation (tDCS) targeting the left DLPFC on cognitive functions related to both symptom domains in adults with ADHD compared to typically developed controls. Method: This pre-registered clinical trial enrolled 55 participants, 25 of whom were diagnosed with ADHD. Participants completed a series of cognitive tasks before and after receiving either tDCS or sham treatment. Results: In the ADHD group, tDCS treatment improved measures associated with inattention, but not measures related to impulsivity. In the control group, tDCS treatment had no benefits. Conclusions: The discrepancy in treatment response observed between inattentive and impulsive symptoms has implications for understanding the neurobiological mechanisms of ADHD. Our findings offer new evidence supporting the positive impact of tDCS on cognitive functions linked to inattention.