Epilepsy
The condition is presented in scripture not by name but by symptom: the seizure-like attacks suffered by a boy whom Jesus heals on the way down from the mountain of transfiguration.
The Boy with the Mute Spirit
The father describes the case to Jesus when the disciples have failed: "Teacher, I brought to you my son, who has a mute spirit; and wherever it takes him, it dashes him down: and he foams, and grinds his teeth, and becomes stiff: and I spoke to your disciples that they should cast it out; and they were not able" (Mr 9:17-18). The clinical picture is precise — onset without warning, falling, foaming at the mouth, clenched jaw, rigid limbs. When the boy is brought into Jesus' presence the same pattern is shown: "immediately the spirit tore him grievously; and he fell on the ground, and wallowed foaming" (Mr 9:20). The chronicity, too, is part of the case: "How much time is it since this has come to him? And he said, From a child. And often it has cast him both into the fire and into the waters, to destroy him: but if you can do anything, have compassion on us, and help us" (Mr 9:21-22). The danger is not the seizure itself but where the seizures throw him — fire, water — and the father's plea is for compassion and help.