A Study to Assess Effectiveness and Efficiency of VNS Therapy in Patients With Difficult to Treat Depression.

A Global PRospective, Multi-cEnter, ObServational Post-markeT Study tO Assess shoRt, Mid and Long-term Effectiveness and Efficiency of VNS Therapy® as Adjunctive Therapy in reaL-world patIents With diFficult to Treat dEpression.

The primary objective of this study is to assess short, mid and long-term clinical outcomes in patients with difficult to treat depression (such as patients with treatment resistant depression) treated with Vagus Nerve Stimulation (VNS) Therapy as adjunctive therapy.

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.

Inclusion Criteria:

• Be at least 18 years of age.
• Have a documented primary diagnosis of chronic (>2 years) or recurrent (2 or more prior episodes) major depressive episode that has not adequately responded to an adequate number of antidepressant treatments, as per local medical standards. This diagnosis must be confirmed using the MINI.
• Provide written Ethics Committee (EC) or Institutional Review Board (IRB) approved informed consent and Health Insurance Portability and Accountability Act (HIPAA, US only) authorization (as applicable according to local requirements).
• Currently is receiving at least one antidepressant treatment (i.e., antidepressant drug, maintenance electroconvulsive therapy, or formal psychotherapy including supportive psychotherapy) or mood stabilizing treatment for bipolar patients (such as lithium, anticonvulsants, or atypical antipsychotics).
• Able and willing to comply with the frequency of (outpatient) clinic visits and to reliably complete all the evaluations as specified in the study protocol.Hence based on the nature of their disease, the following patients should not be included: patients with mental retardation, current severe or significant substance/alcohol abuse, diagnosis of one or more schizophrenia-spectrum or other psychotic disorders, diagnosis of borderline or severe personality disorder as determined by clinical judgment which, in the investigator's opinion, would significantly interfere with subject's participation in the study)

Exclusion Criteria:

There are no exclusion criteria; the investigator should refer to the (local applicable) VNS Therapy Physician's Manual.