Thousands of people with depression who don't respond to drug treatment could be cured by a new device.
Doctors are using a tiny generator to send pulses of electric current to the brain. It has already been used to help epileptics who have seizures which can't be stopped by other methods.
Now neurologists and psychiatrists are looking at Vagal Nerve Stimulation (VNS) to relieve depression.
The device - not much bigger than a matchbox -is implanted in the chest, just under the skin, with a wire running to the vagus nerve in the neck.
It then transmits pulses of extremely low electrical current via the nerve to areas of the brain which influence mood.
Despite impressive advances in the treatment of depression, which affects one in four people in Britain, and the development of modern drugs such as Prozac, a large number of patients have what is known as treatment-resistant depression.
As many as 30 per cent of those affected fail to respond to either drugs or - in some cases - electro- convulsive therapy.
The new implant becomes available in the UK later this year and psychiatrists hope it will help to end the misery suffered by many patients who have run out of treatment options.
Surgery to put the implant in place usually takes less than an hour and is not dangerous.
Although the procedure is performed by a neuro-surgeon, the lead from the implant doesn't go anywhere near the brain.
'It is a relatively straightforward operation,' says psychiatrist Dr Veronica O'Keane. 'The implant is placed in the side of the chest-wall muscle, with a lead reaching the short distance to the vagus nerve in the neck.
'It is noticeable only as a slight bulge under the skin and there are no wires to be seen. Most patients seem to tolerate its presence without complaint.'
Sending electrical impulses via the vagus nerve seems to stimulate two areas deep in the brain - the thalamus and hypothalamus. Both are known to be associated with mood.
'Patients receive a tiny electrical current, just a fraction of one volt,' says Dr Stephen O'Connor, medical director of Cyberonics, the American company which developed the generator implant.
'The electrical pulse happens roughly once every 30 minutes, but it can be adjusted by a computer using infra-red beams aimed at the implant.
'Generally, patients are unaware of the pulse being delivered , although if someone is speaking at the time, it makes their voice go slightly hoarse. It is a very safe device and is easily retrieved if, for any reason, it needs removing.'
Doctors discovered that it may help in depression by accident. A U.S. physician found was that although it did not always control the seizures of epilepsy patients, it did seem to make many of them happier.
Dr O'Keane has just started an implant programme with neuro-surgeons at the Beaumont Hospital in Dublin.
'We have put the implant into three patients since Christmas, though it is too soon to say if it has been a success for these people,' she says.
But we do know - from trials in the U.S. - that this device is helping lift depression where nothing else has worked.
'Treatment-resistant depression is a major problem. I don't think the public realises that so many people still remain unwell despite all the new drugs we have at our disposal.
'These are people who will do anything to be rid of their depression and we have many people who want to have an implant.
But patients will qualify for an implant only if they have had at least three episodes of depression which have failed to respond to existing treatments.'
And Dr O'Keane does sound a note of caution. Like existing treatments, VNS doesn't work for all patients. 'It seems to be effective for around 40 pc of those who try it,' says Dr O'Keane.
'So we still have about 10 to 15 per cent of patients with depression who respond to absolutely nothing. But at least, in VNS, we have something else to try.'
Source : https://www.dailymail.co.uk/health/article-40917/Could-implant-cure-depression.html731