A meta-analysis of randomized sham-controlled trials of repetitive transcranial magnetic stimulation for attention deficit/hyperactivity disorder.

Objective: To investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) for attention deficit/hyperactivity disorder (ADHD).

Methods: Randomized sham-controlled trials were identified in major databases from January 1990 to January 2023. The primary outcome was overall improvement in ADHD symptoms. Subgroup analysis focused on the efficacy of rTMS in different brain regions. Secondary outcomes were the association of rTMS with improvement in different ADHD symptoms. Outcomes were expressed as effect size based on standardized mean difference (SMD)(continuous data), and ORs with 95%CI (categorical data).

Results: A meta-analysis of six randomized sham-controlled trials involving 169 participants demonstrated no difference in overall ADHD symptoms between those treated with rTMS and sham controls (SMD = -0.24, p = 0.17). Subgroup analysis revealed that rTMS was more efficacious than sham treatment when targeting the right prefrontal cortex (SMD = -0.49, p = 0.03) but not the left prefrontal cortex (SMD = 0.01, p = 0.67). rTMS treatment was correlated with greater improvement in inattention (SMD = -0.76, p = 0.0002), but not hyperactivity (p = 0.86), impulsivity (p = 0.41), or depression symptoms (p = 0.95). The apparently higher risk of dropout in the rTMS group than the sham control group was not statistically significant (OR = 1.65, p = 0.26).

Conclusion: This review found that rTMS only had therapeutic efficacy for ADHD symptoms (particularly inattention) when targeting the right prefrontal cortex. Further large-scale randomized sham-controlled trials are required to verify our findings.