Electroconsulvive Therapy (ECT is in this category and most folks are familiar with this therapy through the movies “Its a Beautiful Mind” and “One Flew Over the Cuckoo's Nest”.

The science folks have dialed that neurostimulation therapy way back to where the amperage is between 0.5 - 2 milliamps in DC format for 20 minutes....is what I experienced.

There is an AC version called cranial electrotherapy stimulation which I have not used