Repetitive Transcranial Magnetic Stimulation for Generalized Anxiety Disorder: A Systematic Literature Review and Meta-Analysis
Tapan Parikh, Jeffrey R. Strawn, John T. Walkup, Paul E. Croarkin
Abstract
BACKGROUND: Anxiety disorders such as generalized anxiety disorder (GAD) impact 10% of the US population, and many patients do not completely respond to first-line treatments (e.g., selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and psychotherapy). Given the dearth of evidence for non-pharmacologic, non-psychotherapeutic interventions, we performed a systematic review and meta-analysis of repetitive transcranial magnetic stimulation (rTMS) in adults with GAD. METHODS: A systematic literature review using the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted. Pre- and post-treatment anxiety scores were extracted, and a random-effects meta-analysis was conducted to determine the magnitude of improvement (standardized mean difference). Standard assessments of heterogeneity (e.g., Q-statistic, I2, and τ 2) and publication bias were performed. RESULTS: The initial search resulted in 3194 citations, of which 6 studies were included in the meta-analysis. In total, 152 patients were studied, including 97 patients who received active treatment and 55 who received sham treatment, and heterogeneity was modest (I2 13.32, Q = 5.77). In patients with GAD, rTMS produced a standardized mean difference of -1.857 (confidence interval: -2.219 to -1.494; P < .001) with a prediction interval of -2.55 to -1.16. CONCLUSIONS: The results suggest a robust effect of rTMS in GAD in the context of limited, heterogenous studies. Rigorously designed, randomized controlled trials of rTMS for GAD and related anxiety disorders are urgently needed. These studies will provide opportunities for biomarker development and integration of concurrent evidence-based psychotherapy to maximize results.