Vagus Nerve Stimulation Improves Severe Depression by 70%, Major US Trial Finds
(www.sciencealert.com)
It's worth noting the trial was funded by LivaNova, the company that manufactures the VNS device, which has a financial interest in the trial's outcome.
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The US FDA approved VNS for treatment-resistant depression in 2005, though exactly how it works on depression isn't fully understood.
They make a device with no idea of what it does, then fund a study to see if they can call it a miracle.