τὸ κακὸν δοκεῖν ποτ᾽ ἐσθλὸν τῷδ᾽ ἔμμεν' ὅτῳ φρένας θεὸς ἄγει πρὸς ἄταν
evil seems good, soon or late, to him whose mind the god draws to mischief
When the Gods set their sights on the destruction of a presumptuous man, the most potent tool in their arsenal is madness. This madness often manifests as a loss of reason or memory:
While the word was in the king's mouth, there fell a voice from heaven, saying, O king Nebuchadnezzar, to thee it is spoken; The kingdom is departed from thee...The same hour was the thing fulfilled upon Nebuchadnezzar: and he was driven from men, and did eat grass as oxen, and his body was wet with the dew of heaven, till his hairs were grown like eagles' feathers, and his nails like birds' claws.
Other times this madness can be a frenzied bloodlust, a boon to the noble hero at war that turns to curse at home in peace:
But now that he hath accomplished the labours of Eurystheus, Hera is minded to brand him with the guilt of shedding kindred blood by slaying his own children, and I am one with her. Come then, maid unwed, child of murky Night, harden thy heart relentlessly, send forth frenzy upon him, confound his mind even to the slaying of his children, drive him, goad him wildly on his mad career, shake out the sails of death, that when he has sent o'er Acheron's ferry that fair group of children by his own murderous hand, he may learn to know how fiercely against him the wrath of Hera burns and may also experience mine
Assume the Gods are bound by the laws of physics, our knowledge of science, and the biology of Man's brain. They must then, I suppose, have access to advanced technology (WARNING: TV Tropes Link!!!) to explain how they became gods in the first place.
Using their advanced knowledge of human biology, how can the Gods drive to madness those that they wish to destroy? The madness must be perceived by the victim's fellow man of antiquity to be of uncertain origin; i.e. no kidnapping and lobotomizing and returning the victim to society with a weird scar on his or her head.
Whom the Gods would destroy they first make mad.
The Masque of Pandora, Henry Wadsworth Longfellow