- Objectives: The primary aim of this study was to assess the frequency of post-traumatic stress disorder (PTSD) in patients with the fibromyalgia syndrome (FMS). The influence of gender on measures of PTSD in fibromyalgia (FM) patients also was examined. Methods: Seventy-seven consecutive patients (40 women and 37 men) who fulfilled the criteria for FM were asked to complete questionnaires measuring the prevalence and severity of symptoms of PTSD, anxiety, and depression. The subjects were divided in 2 groups based on the presence or absence of PTSD symptoms. Results: In this study, 57% of the FM sample had clinically significant levels of PTSD symptoms. The FM patients with PTSD reported significantly greater levels of avoidance, hyperarousal, reexperiencing, anxiety, and depression than did the patients without clinically significant levels of PTSD symptoms. The prevalence of PTSD among the FM patients in this study was significantly higher than in the general population. Women with FM and PTSD reported a greater number of past traumatic events than did their male counterparts. Conclusions: The results represent the first comprehensive study applying structured clinical assessment of trauma exposure and PTSD to a group of FM patients. This study shows a significant overlap between FM and PTSD, according to the currently accepted diagnostic criteria for each. Semin Arthritis Rheum 32:38-50. Copyright 2002, Elsevier Science (USA). All rights reserved.