a1 Department of Psychiatry, University Hospital, Bern, Switzerland
a2 Department of Psychiatry and Psychotherapy, University Hospital, Bonn, Germany
a3 Departments of Psychiatry and Mental Health, The Johns Hopkins University, Baltimore, MD, USA
a4 Psychiatrische Klinik der FU Berlin, Berlin, Germany
a5 Beaumont Hospital, Department of Psychiatry, Dublin, Ireland
a6 University Hospital Umea, Umea, Sweden
a7 National Hospital for Neurology and Neurosurgery, Department of Neuropsychiatry and Neurology, London, UK
a8 Evangelisches Krankenhaus Bielefeld, Bielefeld, Germany
a9 Alcohol Rehabilitation Clinic, Wilhelmsdorf, Germany
a10 Departments of Psychiatry and Psychotherapy, Ludwig-Maximilian-University, Munich, Germany
a11 University Hospital Gent, Gent, Belgium
a12 Ninewells Hospital and Medical School, Department of Psychiatry, Dundee, UK
a13 Lindenhof Hospital, Department of Neurosurgery, Bern, Switzerland
Background Vagus nerve stimulation (VNS) therapy is associated with a decrease in seizure frequency in partial-onset seizure patients. Initial trials suggest that it may be an effective treatment, with few side-effects, for intractable depression.
Method An open, uncontrolled European multi-centre study (D03) of VNS therapy was conducted, in addition to stable pharmacotherapy, in 74 patients with treatment-resistant depression (TRD). Treatment remained unchanged for the first 3 months; in the subsequent 9 months, medications and VNS dosing parameters were altered as indicated clinically.
Results The baseline 28-item Hamilton Depression Rating Scale (HAMD-28) score averaged 34. After 3 months of VNS, response rates (50% reduction in baseline scores) reached 37% and remission rates (HAMD-28 score <10) 17%. Response rates increased to 53% after 1 year of VNS, and remission rates reached 33%. Response was defined as sustained if no relapse occurred during the first year of VNS after response onset; 44% of patients met these criteria. Median time to response was 9 months. Most frequent side-effects were voice alteration (63% at 3 months of stimulation) and coughing (23%).
Conclusions VNS therapy was effective in reducing severity of depression; efficacy increased over time. Efficacy ratings were in the same range as those previously reported from a USA study using a similar protocol; at 12 months, reduction of symptom severity was significantly higher in the European sample. This might be explained by a small but significant difference in the baseline HAMD-28 score and the lower number of treatments in the current episode in the European study.
(Received April 12 2007)
(Revised December 04 2007)
(Accepted December 10 2007)
(Online publication January 04 2008)