Vagus Nerve Stimulation for Treating Adults With Severe Fibromyalgia

Inclusion Criteria: * Diagnosis of FMS for at least 2 years, as according to the 1990 guidelines of the American College of Rheumatology (ACR) criteria. In addition, ruling out of any other medical illness to which pain may be attributed. * Inadequate relief in FMS pain despite good treatment efforts using standard pharmacological pain management. Only patients who are work-disabled because of FMS pain are eligible for study participation if they are on opioid maintenance therapy. * Overall FMS pain at an intensity of 5 or greater on a 0-10 verbally anchored pain intensity scale, on more than 50% of days over a consecutive 7-day period before study entry * Has not changed pharmacological and/or non-pharmacological (e.g., yoga, exercise) treatment regimen for the 4 weeks before the first study visit and continues to experience severe pain * At least average premorbid IQ, as assessed by the vocabulary subtest of the WAIS-III, which is a standardized, well-validated index of premorbid intellectual function * Willing to use an acceptable method of birth control * Able to comply with all testing and follow-up visit requirements defined by the study protocol * Currently lives within a 2-hour driving commute to the study site Exclusion Criteria: * Rheumatologic condition other than FMS * Secondary FMS, in which FMS is comorbid with another rheumatologic condition * Reports that FMS pain began after a physical trauma * In litigation that is associated with FMS condition at study entry * Severe lifetime or current diagnosis of psychotic depression, bipolar disorder, schizophrenia, schizoaffective disorder, or other psychotic disorders or has a clear history of other psychiatric illness before the onset of FMS * Diagnosed with major depressive disorder and has attempted to commit suicide in the past or has active suicidal ideation * Lifetime or current history of dependence or abuse of pain medication or alcohol * Treatment with an antipsychotic drug within 3 months of study entry * Demonstrated a known placebo response in a previous study * Treatment with botulinum toxin or local steroid injection for FMS within 2 months of study entry * History of myocardial infarction or cardiac arrest * Received general anesthesia within 30 days of implantation surgery * Treatment with an investigational drug within a clearance duration of five times the half-life of the investigational drug or within 4 weeks of study entry * Currently using another investigational device or dru…