What does this rating mean?
Vagus nerve stimulation (VNS) is a medical treatment where a device similar to a pacemaker is implanted into the chest. A wire leading out of the device is passed under the skin and connected to the left vagus nerve in the neck. This nerve is connected to the brain. VNS involves periodically stimulating this nerve with electrical signals.
A newer type of VNS has been developed that does not require surgery. In non-invasive or transcutaneous (across the skin) VNS (tVNS), the vagus nerve is stimulated with a device that is placed on the skin over the vagus nerve. Usually, this device is placed in the outer part of the ear.
Surgical VNS is sometimes used as a treatment for depression for people who have not responded well to other forms of treatment. VNS is more commonly used to treat other disorders such as epilepsy.
It is not clear exactly how VNS might help treat depression. The vagus nerve is connected to brain areas involved in mood regulation. Stimulating this nerve might help restore chemical imbalances involved in depression.
Only one randomized controlled trial has been conducted on VNS for people with diagnosed depression. Participants in this study who received VNS did not experience any greater reduction in their depression symptoms than those who received a placebo (dummy) treatment.
Many more studies have been conducted where the treatment was not compared to a placebo, often with people for whom other depression treatments have not been effective. In these studies, more people experienced a reduction in depression symptoms if they had the VNS treatment compared to people who had only their regular treatment (for example, antidepressant medication). However, because there was no placebo group to compare to in these studies, we cannot be sure that the VNS intervention caused this effect.
More studies of better quality are needed to understand the effectiveness of VNS for depression.
Traditional VNS is an invasive procedure and requires surgery under general anesthetic to implant the device. It is also an expensive procedure which may not be covered by Medicare. It may be many months before an improvement in symptoms is noticed. Side effects can include neck pain, voice changes, coughing, headaches and chest pain, amongst others.
Non-invasive VNS does not require surgery, but it is not a widely accessible treatment.
VNS is only available for people whose depression has not responded to conventional treatment. A referral to a specialist doctor is required.
There is not enough good evidence at this stage to recommend vagus nerve stimulation as a treatment for depression.
Last reviewed and updated: 22 December 2023
These treatments are very useful. They are strongly supported as effective by scientific evidence.
These treatments are useful. They are supported by scientific evidence as effective, but the evidence is not as strong.
These treatments are promising and may be useful. They have some evidence to support them, but more evidence is needed to be sure they work.
