Transcranial magnetic stimulation as a treatment for posttraumatic stress disorder: A meta-analysis

Background: Posttraumatic stress disorder (PTSD) is a pervasive mental health condition with limited treatment success. Transcranial magnetic stimulation (TMS) has shown positive outcomes for people with PTSD, using different treatment protocols. This meta-analysis sought to examine which variables in TMS treatment are associated with treatment benefits. Methods: A literature search of major online research databases from inception to September 15, 2020 was conducted to identify primary research studies using TMS to treat PTSD. Treatment effect data and TMS treatment variables were coded and analysed using a random effects model. Meta-regression and analyses of moderating variables were conducted to ascertain which variables were associated with significant treatment effects. Results: An overall effect size of d = 1.17, 95% CI [0.89-1.45] for TMS as a treatment for PTSD was found. Analysis of moderators showed that there was a significantly larger treatment effect for high frequency TMS (d = 1.44) compared with low frequency (d = 0.72), p = .006; there was no significant difference between TMS targeting the left dorsolateral prefrontal cortex (DLPFC) and the right DLPFC; and larger treatment doses were not associated with stronger treatment effects. Limitations: Not all published studies were available in English or reported the necessary data to be included in this meta-analysis. Conclusions: TMS shows potential as a treatment for PTSD, although further research is required to understand the neurological mechanisms of TMS on specific PTSD symptoms so that more effective treatment can be designed for individuals.