Repetitive Transcranial Magnetic Stimulation for Depression and Posttraumatic Stress Disorder in Veterans With Mild Traumatic Brain Injury.

OBJECTIVES: Mild traumatic brain injury (mTBI) is a signature injury of military conflicts and is prevalent in veterans with major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). Although therapeutic transcranial magnetic stimulation (TMS) can reduce symptoms of depression and PTSD, whether traumatic brain injury (TBI) affects TMS responsiveness is not yet known. We hypothesized mTBI would be associated with higher pretreatment symptom burden and poorer TMS response.

MATERIALS AND METHODS: We investigated a registry of veterans (N = 770) who received TMS for depression across the US Veterans Affairs system. Of these, 665 (86.4%) had data on TBI and lifetime number of head injuries while 658 had complete data related to depression outcomes. Depression symptoms were assessed using the nine-item Patient Health Questionnaire and PTSD symptoms using the PTSD Checklist for DSM-5. Linear mixed effects models and t-tests evaluated whether head injuries predicted symptom severity before treatment, and how TBI status affected clinical TMS outcomes.

RESULTS: Of the 658 veterans included, 337 (50.7%) reported previous mTBI, with a mean of three head injuries (range 1-20). TBI status did not predict depressive symptom severity or TMS-associated changes in depression (all p's > 0.1). TBI status was associated with a modest attenuation of TMS-associated improvement in PTSD (in patients with PTSD Checklist for DSM-5 scores > 33). There was no correlation between the number of head injuries and TMS response (p > 0.1).

CONCLUSIONS: Contrary to our hypothesis, presence of mTBI did not meaningfully change TMS outcomes. Veterans with mTBI had greater PTSD symptoms, yet neither TBI status nor cumulative head injuries reduced TMS effectiveness. Limitations include those inherent to retrospective registry studies and self-reporting. Although these findings are contrary to our hypotheses, they support the safety and effectiveness of TMS for MDD and PTSD in patients who have comorbid mTBI.