Steve Collins is a 45-year-old unemployed architect who has been living with severe depression for 15 years. “I’m like a hermit crab hiding under rocks, crouching in dark spaces and only venturing out occasionally; there’s no light, no hope, no way in or out. I’ve been in therapy for years and must have taken at least six different antidepressant drugs. I had ECT (electroconvulsive therapy) and that literally shocked me out of it for a bit, but the depression came back – and the idea of ECT was so shocking for my family. People say: ‘Well, at least you haven’t got cancer.’ But, honestly, I’d rather have almost anything than live like this.”
A new type of treatment, vagal nerve stimulation (VNS), may offer hope for people like Collins who don’t improve with conventional depression treatment. A small battery-powered device like a pacemaker is inserted under the skin in the neck, from where it emits pulses of weak electical current to stimulate part of the vagus nerve. The vagus normally monitors our vital functions; it collects information about our breathing, heart rate and joint position, and sends signals back to the brain that tell it to respond if there are fluctuations.
No one fully understands how VNS works in severe depression that has been unresponsive to other treatments, admits psychiatrist Prof Hamish McAllister-Williams, of Newcastle University. “We don’t know exactly how lots of treatments work in psychiatry, including antidepressant drugs. I’m more interested in whether something works and, in the case of VNS, I’m persuaded that it does.” He cites two recent studies supporting the role of VNS, in addition to the usual treatment options of drugs, talking therapies and ECT. He says it’s likely to be a true effect, not just a placebo, because a placebo tends to kick in quickly – and wear off quickly – whereas VNS takes six months to work, but at least half of those who respond, remain well. It may be particularly effective with people like Collins, who have improved after ECT, but whose depression keeps on returning.