Objective:

To estimate the pooled effect of low-frequency (predominantly 1 Hz), non-neuronavigated rTMS versus sham stimulation on Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores, and to determine whether stimulation target, treatment duration, or frequency systematically moderates that effect.

Approach:

• Systematic Review and Meta-Analysis: Conducted a PRISMA 2020-compliant systematic review and meta-analysis of sham-controlled RCTs reporting Y-BOCS total scores, assessing risk of bias and performing subgroup analyses.

Key Findings:

• Fourteen RCTs (N = 460; 252 active rTMS, 208 sham or control) were included.
• The primary pooled analysis showed a mean difference (MD) in Y-BOCS scores of −0.69 (95% CI: −1.75 to 0.38; P = 0.21; I² = 58%), indicating no statistically significant benefit of rTMS over sham.
• Moderate heterogeneity was substantially reduced by excluding an outlier trial.
• Subgroup analyses by stimulation target, treatment duration, and frequency were non-significant.

Interpretation:

Pooled evidence does not support a statistically significant benefit of low-frequency, non-neuronavigated rTMS over sham for OCD symptom reduction.

Limitations:

• The review focused exclusively on low-frequency, non-neuronavigated surface-coil protocols and did not evaluate FDA-cleared deep TMS approaches.
• Moderate heterogeneity was present, though reduced by excluding an outlier trial.

Conclusion:

This low-frequency, non-navigated protocol class lacks demonstrated efficacy in controlled trials.