Self-induced? I was working on a project a while ago. Whether it'll work as a method, is still up for debate and I probably wouldn't recommend it due to risks involved, but what you do is utilizing your adrenaline until your pulse gets high you get dizzy (180-200+ bpm), then during the peak, you perform an all-out valsalva maneuver. Right then and there, of you haven't died from the high adrenaline, the intracranial hypertension/subarachnoid hemorrhage should do it, either by injury or an adrenaline storm.