Transcranial direct current brain stimulation decreases impulsivity in ADHD

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Impulsivity is a key symptom of Attention Deficit Hyperactivity Disorder (ADHD).
• Dorsolateral prefrontal cortex (DLPFC) transcranial direct current stimulation (tDCS) may enhance cognitive control, potentially improving impulse control in ADHD.

Purpose of the Study:

• To investigate the efficacy of tDCS applied to the left DLPFC in reducing impulsivity in adults with ADHD.
• To assess the impact of tDCS on performance in the Conners Continuous Performance Task (CPT) and Stop-Signal Task (SST).

Main Methods:

• A within-subject, double-blind, counterbalanced study involving 37 adult ADHD participants.
• Participants received three sessions of either active tDCS (2.0 mA) or sham stimulation over the left DLPFC, with two-week intervals between stimulation periods.
• Cognitive tasks, including the CPT and SST, were administered at baseline, post-treatment, and a 3-day follow-up.

Main Results:

• A significant reduction in false positive errors on the CPT was observed in the tDCS group compared to sham, from baseline to end of treatment (p < 0.001).
• This improvement in CPT false positive scores did not persist at the follow-up assessment.
• No significant effects of tDCS were found on CPT true positive errors, response time, or Stop-Signal Task reaction time.

Conclusions:

• Left DLPFC tDCS demonstrates potential for improving specific impulsivity-related errors (false positives) in adult ADHD.
• These findings support the therapeutic potential of tDCS as an intervention for certain symptoms in adult ADHD patients.