Transcranial magnetic stimulation for posttraumatic stress disorder: an updated systematic review and meta-analysis

Introduction Transcranial magnetic stimulation (TMS) is a promising non-pharmacological intervention for posttraumatic stress disorder (PTSD). However, randomized controlled trials (RCTs) and meta-analyses have reported mixed results. Objective To review articles that assess the efficacy of TMS in PTSD treatment. Methods A systematic review using MEDLINE and other databases to identify studies from the first RCT available up to September 2015. The primary outcome was based on PTSD scores (continuous variable). The main outcome was Hedges' g. We used a random-effects model using the statistical packages for meta-analysis available in Stata 13 for Mac OSX. Heterogeneity was evaluated with I2 (> 35% for heterogeneity) and the χ2 test (p < 0.10 for heterogeneity). Publication bias was evaluated using a funnel plot. Meta-regression was performed using the random-effects model. Results Five RCTs (n = 118) were included. Active TMS was significantly superior to sham TMS for PTSD symptoms (Hedges' g = 0.74; 95% confidence interval = 0.06-1.42). Heterogeneity was significant in our analysis (I2 = 71.4% and p = 0.01 for the χ2 test). The funnel plot shows that studies were evenly distributed, with just one study located marginally at the edge of the funnel and one study located out of the funnel. We found that exclusion of either study did not have a significant impact on the results. Meta-regression found no particular influence of any variable on the results. Conclusion Active TMS was superior to sham stimulation for amelioration of PTSD symptoms. Further RCTs with larger sample sizes are fundamental to clarify the precise impact of TMS in PTSD.