Noninvasive Brain Stimulation in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis of Treatment Efficacy and Targeting Strategies.

OBJECTIVE

Noninvasive brain stimulation (NIBS) has emerged as a promising novel treatment for attention-deficit/hyperactivity disorder (ADHD). However, the precise effects of NIBS in ADHD, as well as optimal stimulation protocols, remain elusive. This systematic review and meta-analysis aimed to provide a rigorous evaluation and robust quantified evidence on the therapeutic efficacy of NIBS on ADHD.

METHOD

A systematic search of PubMed, Web of Science, and Embase identified 59 studies [repetitive transcranial magnetic stimulation (rTMS): 11; transcranial direct current stimulation (tDCS): 35; other NIBS: 13]. We included 33 randomized controlled trial studies (7 for rTMS, 26 for tDCS; 1,049 individuals with ADHD) in meta-analyses of therapeutic efficacy. We performed subgroup analyses to investigate the impact of stimulation targets on therapeutic outcomes and included meta-regression analyses to evaluate the dose-response relationship.

RESULTS

NIBS has favorable tolerability but evidence for its therapeutic efficacy in ADHD remains inconclusive. Meta-analyses indicated that rTMS was effective in alleviating inattention symptoms (Hedges's g=-1.44, p=0.002), reducing hyperactivity/impulsivity symptoms (Hedges's g=-0.95, p=0.005), and improving attention-related functions (Hedges's g=0.53, p=0.023), and tDCS showed therapeutic benefits in reducing hyperactivity/impulsivity symptoms (Hedges's g=-0.28, p=0.024) and improving inhibitory control (Hedges's g=0.39, p=0.028). tDCS positioned over the left dorsolateral prefrontal cortex (DLPFC) and right orbitofrontal cortex (OFC) demonstrated significant effects in improving inhibitory control. No significant dose-response relationship was found for either tDCS or rTMS in ADHD.

CONCLUSION

Our meta-analysis supports the therapeutic potential of NIBS in ADHD, revealing domain-specific benefits across different stimulation devices and sites. Although more data are needed, NIBS shows promise as an intervention for ADHD.

DIVERSITY & INCLUSION STATEMENT: We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. Diverse cell lines and/or genomic datasets were not available. We actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our author group. We actively worked to promote sex and gender balance in our author group. While citing references scientifically relevant for this work, we also actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our reference list. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list. The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work.

STUDY REGISTRATION INFORMATION

Efficacy of Noninvasive Brain Stimulation and the Impact of Targeting in Attention Deficit/Hyperactivity Disorder: An Updated Systematic Review and Meta-Analysis; https://osf.io/bmhax.