Adjunctive vagus nerve stimulation for treatment-resistant depression: a preliminary study

Abstract

Background This study is the first to assess the safety and therapeutic efficacy of vagus nerve stimulation (VNS) as an adjunctive treatment for Chinese patients suffering from treatment-resistant depression (TRD). Methods A total of seven patients with TRD underwent surgical implantation of a VNS device were followed over a 9-month period. The 24-item Hamilton Rating Scale for Depression (HAMD-24) and the 14-item Hamilton Anxiety Scale (HAMA) were used to assess depressive and anxiety symptoms, respectively. Neurocognitive function was measured with the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Memory Scale (WMS). Results After 3 months of treatment with VNS, the antidepressant response and remission rates were 42.9% and 28.6%, respectively. After 9 months of treatment with VNS, the response and remission rates increased to 85.7% and 57.1%, respectively. Significant time main effects were identified for HAMD-24 scores, HAMA scores, the WMS memory quotient, and the full intelligence quotients measured with the WAIS (all ps < 0.05). The most frequent adverse effects of VNS treatment were voice alteration (100%) and cough frequency increase (71.4%). Conclusion This preliminary study indicated that adjunctive VNS was effective and safe in treating Chinese patients who were suffering from TRD, and its efficacy increased with time. Key points There is positive evidence to support the role of VNS as an adjunctive treatment in Chinese patients with TRD. The antidepressant efficacy of adjunctive VNS for Chinese patients with TRD increased with time. The most frequent adverse effects of VNS treatment were voice alteration and cough frequency increase.