BACKGROUND
Efficacy of repetitive transcranial magnetic stimulation (rTMS) against attention-deficit/hyperactivity disorder (ADHD) remains unclear.
OBJECTIVE
To investigate the treatment efficacy of rTMS against the symptoms of ADHD as well as identifying the potential factors that may affect the therapeutic efficacy of rTMS through subgroup analysis.
METHODS
Randomized sham-controlled trials (RCTs) were identified from major databases from inception to January 2022. Primary outcome was improvement in total symptoms of ADHD. Subgroup analysis focused on rTMS efficacy targeting different brain regions. Secondary outcomes were associations of rTMS with improvements in different symptoms. Outcomes were expressed as effect size (ES) based on standardized mean difference (SMD) (continuous data), and odds ratios (ORs) with 95% confidence interval (CI) (categorical data).
RESULTS
Meta-analysis of six RCTs involving 169 participants demonstrated no difference in total ADHD symptoms between rTMS-treated participants and sham controls (SMD=-0.24, p=0.17). Subgroup analysis revealed better efficacy of rTMS than sham controls when targeting rPFC (SMD=-0.49, p=0.03), but not lPFC (SMD= 0.01, p=0.67). rTMS treatment correlated with better improvement in symptoms of inattention (SMD=-0.76, p=0.0002), but not hyperactivity (p=0.86), impulsivity (p=0.41), and depression (p=0.95). The apparently higher risk of dropout in the rTMS group than sham controls was not statistically significant (OR=1.65, p=0.26).
CONCLUSIONS
Our study only supported the therapeutic efficacy of rTMS targeting rPFC for the symptoms of ADHD, especially inattention, but not that targeting lPFC. Further large-scale randomized sham-controlled trials are required to verify our findings.
CLINICALTRIAL
PROSPERO CRD42023393713