Wells

The population under study comprises a real-world patient population with difficult to treat depression: patients diagnosed with unipolar or bipolar disorder with chronic or recurrent depression who fail to achieve an adequate response to standard psychiatric management. The diagnosis of depression and comorbid disorders will be determined based on the Mini International Neuropsychiatric Interview (MINI). A minimum of five hundred (500) patients will be implanted with a VNS Therapy System and up to eighty (80) sites may participate in this study. Enrollment will take 8 years, based on competitive enrollment. For each subject a baseline visit will occur between 1 and 6 weeks before implant. Once implanted with the device, subjects will be followed-up for a minimum of 36 months and a maximum of 60 months. The study may stop when the last subject has reached the 36 months follow-up.