Apparently ergot was suggested over the years, but the symptoms don't match up (it sez here). Ergot has also been blamed for the Salem Witch Trials -- that seems to me to have been due to the fact that human beings, for all our good qualities, can be giant a-holes.
There is also reason to attribute panics about witches in Europe to their promotion of herbal salves and potions containing toxic, mind-altering alkaloids. In effect, outraged locals were in an uproar against witches who were peddling drugs, often to local teens. With that in mind, many accounts of magic by witches sound like contemporary descriptions of acid trips, with occasional violent episodes corresponding to what cops and ERs today recognize as drug psychosis.
Early humans, the ancient Greeks and others, and even aboriginals today all aimed at altered states through herbal preparations of one sort or another. Even smoking a peace pipe was more or less a session of getting buzzed on tobacco. Of course, being primitives, they lacked the whiskey or brandy that modern man knows to be the perfect accompaniment to strong cigars!
Maybe the whole world is on drugs now? It seems that way in some areas where killing is done for kicks.