Further Thoughts on Cannibal Attacks

More discussion following the recent posts about the Miami cannibal attack. Thanks to James Smith for his thoughtful contributions.
James Smith: Speculation being what it is, it's hard to say--but there's certainly precedent (think the Vikings, to  name just one group) for somebody consuming some  mind-altering drug or combination thereof and believing  themselves to be a wolf, bear or other dangerous animal  admired for its fighting prowess...the difference is, ancient  people did this as a function of their society, not acting  out on their own. 
Gordon Grice: Hard to know how much of history is true, but  there are precedents in chronicles and myth for "anti-social"  predation on fellow humans. Sawney Beane and his clan come to  mind. 
James Smith: While Sawney Beane's story is a little confused  as to exact time (probably due to confusion between James I  of Scotland or James VI of Scotland/I of England) and  probably prone to some exaggeration, there is no real reason  to doubt its essential points. I actually had a pet kingsnake  named Sawney when I was a teenager (the reason for the name  is, I'm sure, obvious.) The Beanes, though, didn't seem to be motivated (from what we  can gather) by psychosis or drugs...Sawney and his wife  simply fell back on eating people during lean times and  taught their children and grandchildren that this was normal.  It has sometimes occurred to me that the legends of  werewolves and child-eating witches probably represent  earlier societies' attempts to rationalize and explain the  deviant behavior of anti-social predators, a la Albert Fish, for instance. 
Gordon Grice: That's an interesting idea, James. Probably the best evidence for it is scarcity of serial killer stories in history prior to the Victorian era. I've heard that fact used as a basis for arguing that serial murder is a modern phenomenon, but it seems more likely to me that myths of ogres and the like are earlier ways of understanding aberrant murder and cannibalism. I'm skeptical of the specifics about the Beanes, as the whole story seems to reek of ogre-mythology. But the premise that people could establish a cannibal custom within a society that abhors it has precedent in well-attested cases like that of Fritz Haarman. (It also has precedent among chimpanzees, by the way.)
Werewolves as real-life cannibals also makes sense to me. Our friend Guy Endore implies just such a connection in his novel The Werewolf of Paris, which plays lycanthropic variations on the case of Sgt. Bertrand. In fact, even in Roman times it seems as if lycanthropy was an explanation, or maybe just a metaphor, for drunkenness and rape. (There's the drug connection again.)
I'm skeptical regarding the witchcraft part. When William Arens reviewed the literature on cannibalism, he found it was often attributed to a culture by its enemies, but in most cases, other evidence was lacking. I think that's what's at work in reports of witchcraft practices. In the Renaissance, accusations of witchcraft were frequently leveled against heretical sects. Baby-eating was part of that slander; it was a way the Church had of demonizing its enemies. The same accusations were made against Jews. So I suspect those particular allegations were politically motivated, not based on any reality. I also suspect that sort of motive behind the accusations against, for example, Gilles de Rais, who supposedly murdered hundreds of children for giggles.