Depression is characterised by low mood, loss of interest and enjoyment in life, and a range of associated emotional, cognitive, physical and behavioural symptoms. Depression is treatment-resistant when symptoms have not improved after at least 2 standard treatments.
The diagnosis and management of depression is described in the NICE guidelines on depression in adults and depression in children and young people. Standard treatment for depression includes antidepressants or psychological therapies (including cognitive behavioural therapies) or a combination of both. In severe depression when multiple treatments have failed, electroconvulsive therapy or other forms of neurostimulation are sometimes used.
The aim of implanted vagus nerve stimulation for treatment-resistant depression is to reduce symptoms and improve mood by periodic stimulation of the vagus nerve.
The procedure is done using general or local anaesthesia. An incision is made on the left side of the neck and the left vagus nerve is identified. A stimulator electrode is put around the nerve and the leads of the electrode are guided under the skin to the left chest wall. They are attached to a pulse generator unit, which is implanted into a subcutaneous pocket. The stimulator settings can be adjusted or turned off using an external (wireless) programming device.