Use of transcutaneous auricular vagus nerve stimulation (taVNS) in the treatment of drug-resistant depression - a pilot study, presentation of five clinical cases

Aim. The aim of the study was to assess safety and efficacy of transcutaneous vagus nerve stimulation (taVNS) as the method added to standard pharmacotherapy in the group of patients with treatment-resistant depression. Methods. We present results of pilot study involving the use of commercially available transcutaneous vagus nerve stimulators. With external, non-invasive nature of new solution, the patient is avoiding possible side effects of surgical operation. taVNS is a relatively new, noninvasive VNS method based on the location of afferent vagus nerve distribution on the surface of the ear. The pilot study group consisted of 5 patients with treatment-resistant depression. All patients suffered from severe depression with no response to appropriate courses of at least two different antidepressants. The assumed observation time was 12 weeks. The duration of stimulation was 4 hours/day, divided in 2 sessions. Mental state was assessed by clinician with the use of the Hamilton Depression Rating Scale (HAMD-17) and the Clinical Global Impression Scale (CGI). Results. In 2 cases substantial improvement of mental state was observed (significant improvement in scoring scales, improvement of mood and drive, decrease of anxiety). 3 patients resigned from the study because of difficulties in handling devices. Conclusions. Vagus nerve stimulation may represent major advance in management of chronic and treatment-resistant depression. taVNS could represent safer alternative to previously used invasive methods. The results can be observed after few weeks or even few months of therapy. Because of the possible long-term benefits and side-effects of taVNS, further clinical trials are required to assess its effectiveness.