Fibromyalgia Syndrome (FMS) is a persistent debilitating disorder estimated to impair the quality of life of 2–4% of the population. FMS is an important representative example of central nervous system sensitization, associated with abnormal brain activity, that can be triggered by traumatic brain injury (TBI), nervous system infections (EBV, CMV) and severe persistence emotional stress. The goal of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on symptoms and brain activity in women suffering from FM triggered by childhood sexual abuse (CSA).