There are things I need to ask her. Not what happened, back then in the time I lost, because now I know that. I need to ask her why. If she remember… - Margaret Atwood

“All it takes,” said Crake, “is the elimination of one generation. One generation of anything. Beetles, trees, microbes, scientists, speakers of French, whatever. Break the link in time between one generation and the next, and it’s game over forever.”

However, there are all sorts of behaviours in the Bible that might be called mad now, but aren't designated as insanity by the text itself. People see visions — of angels going up and down ladders, of fiery chariots — and, like Moses, who hears a bush talking, and Balaam the prophet who has a conversation with his donkey, they hear voices of those who cannot be said to be present in any usual sense of the word. They also speak in tongues, as the disciples do at Pentecost. Like madness, the visions, the voices and the speaking in tongues are due to external and usually divine agencies. In a world so permeated with supernatural powers, there are no accidents, and in one so riddled with prophets — who went into a frenzy while prophesying — many more kinds of behaviour were accepted as normal, at least for a prophet or an inspired person, than would be the case now. John the Baptist, dressed in animal skins and wandering around in the wilderness denouncing his social superiors, was not thought of as a de-institutionalized street person who's gone off his medications, but as a saint. And this was the pattern for mediaeval views of aberrant behaviour — if you were acting crazy it was a divine punishment, or else you were possessed, by powers either divine or demonic — perhaps aided, in the latter case, by witches.

For every age there is a popular idea about what madness is, what causes it, and how a mad person should look and behave; and it's usually these popular ideas, rather than those of medical professionals, that turn up in songs and stories and plays and books.