My dad has had deep brain stimulation (not the same as vagnus nerve stimulation, but in the same area) for over ten years. It helps a lot with his dystonia but

My dad has had deep brain stimulation (not the same as vagnus nerve stimulation, but in the same area) for over ten years. It helps a lot with his dystonia but he has developed severe paranoia which gets progressively worse. Of course you can't say that one caused the other, but I think it is reasonable to be cautious about devices that put electricity in your brain. Benefits are often instant side-effects may slowly accumulate over the years.