Review: Transcranial direct current stimulation in ADHD shows clinical effects

If children are constantly fidgeting, impulsive and unfocused, this may in some cases be due to attention deficit hyperactivity disorder (ADHD). This disorder is particularly problematic in everyday school life and impairs the development of the affected children and adolescents. Transcranial direct current stimulation (tDCS) could be helpful here. In a review, IfADo PhD student Ali Salehinejad and neuroscientists from Iran, Netherlands and Italy critically analyzed already published studies. The review is currently published in the journal „Neuroscience Bulletin“.

Ten of the 14 studies showed at least a gradual improvement in cognitive deficits (reaction inhibition, working memory, attention, cognitive flexibility) or clinical symptoms (e.g. impulsiveness, inattention). The most prominent positive effects were seen when the left frontal part of the cerebral cortex was treated. In adults with ADHD, a current intensity of 2 milliamperes was associated with a significant improvement, whereas 1 milliampere was sufficient in children. Four studies showed no significant or only very small effects. No serious adverse effects during or after tDCS were reported in the studies.

Application depends on individual symptoms

Ali Salehinejad summarizes that the type of tDCS application should be tailored to the individual patient. On the one hand, the different symptoms are related to different brain regions. On the other hand, it might be advantageous to adapt to stimulation parameters such as intensity and duration to the individual patient. Particularly in children, it should also be taken into account that they are still developing.

Overall, tDCS appears to be a promising method for improving ADHD deficits. However, the clinical use of tDCS in ADHD requires further systematic investigations with larger samples.