- Abstract Background: Transcranial magnetic stimulation (TMS) has become, over the last few years, a promising avenue for new research in affective disorders. In this study we have evaluated the clinical effect of slow TMS on posttraumatic stress disorder (PTSD) symptoms. Methods: Ten PTSD patients were given one session of slow TMS with 30 pulses of 1 m/sec each, 15 to each side of the motor cortex. Results: Symptoms of PTSD were assessed by using three psychological assessment scales, at four different time points. In this first, pilot, open study, TMS was found to be effective in lowering the core symptoms of PTSD: avoidance (as measured by the Impact of Event Scale), anxiety, and somatization (as measured by the Symptom Check List–90). A general clinical improvement was found (as measured by the Clinical Global Impression scale); however, the effect was rather short and transient. Conclusions: The present study showed TMS to be a safe and tolerable intervention with possibly indications of therapeutic efficacy for PTSD patients.