Is epilepsy mentioned in the Bible?

These are clearly distinguished in Matt. 4:24 from those possessed by demons. The word is σεληνιαζόμενοι, which, like the word lunatic, is derived from 'the moon,' and is thought to embrace epileptics as well as those of unsound mind. The lad in Matt. 17:15 is called a lunatic, but he was also possessed by a demon: in Mark 9:25 it is called a 'dumb and deaf spirit.'

I quite agree with Dr. Trench that possession means possession; the case of Legion leaves no manner of doubt. But, whatever Mede and others may say, these cases are expressly distinguished from lunacy, as in Matthew 4:24; and not only do the Evangelists speak of devils coming out, but the Lord expressly desires them to come out. And the case of Legion seems given expressly to shew it is really so, as one of the "Fathers" remarks. Even now, with all their boasting, in cases of epilepsy the doctors on post-mortem examinations fail generally to find any adequate trace of disease. Scientific men have to learn that they are not all the world; and Christians who are afraid through their pretensions, and yield to semi-rationalism, are the most contemptible of all writers. Milman says our Lord adopted the current language of the day because unbelief in spiritual agency was one of the characteristic tenets of the unpopular sect of the Sadducees; as if the Lord Jesus would maintain as a truth in the minds of the people a false doctrine on a most important point where the Sadducees were right, for fear of losing His popularity by identifying Himself with them by speaking the truth. Why should He even have said anything and not merely heal the sick person? It is next door to blasphemy. Meyer says, all the efforts to explain away the history of Legion are useless: either you must take it as a true history; or recognise legendary parts and separate them, and take the story of the swine as the reminiscence of some mishap. He is as unbelieving on these points as the rationalists could wish. Lange's explanation, which Canon Farrar has borrowed, Meyer treats with the contempt it deserves.

162 There are various forms of disease. In a general way all come from the evil one; but in the sense of "possession," his power cannot be applied to all of them: such diseases may be accompanied by possession or not; and so they are treated in scripture. We find the Lord healing diseases and casting out devils. We find lunatics and demoniacs distinguished in the same phrase.

It has been argued that the persons said to be possessed were really lunatics, who imagined they were possessed; and to meet that fancy the Lord spoke to the supposed spirit and told it to come out! But this is simply an effort to deny the power of Satan and his emissaries over man, and also God's power in the miracles. The Lord spoke of the casting out of demons when he was not speaking to those possessed. The demons also knew the Lord to be the Son of God, answered Him, asked permission to go into the herd of swine, and feared he had come to punish them before the time. Those who were lunatics are mentioned along with, and as different from, those possessed with demons. Matt. 4:24. It is true that the father of a lad who was possessed by a demon called him a lunatic, and said the disciples could not cure him, in Matt. 17:14-16; but in Mark 9:17 he said his son had a dumb spirit, and in Luke 9:39 'a spirit taketh him.' It was clearly a case of possession: the Lord rebuked the demon, and it departed from him.

This passage is most important, as from it and other scriptures it is plain that demon-possession is distinct from disease, though the two are often, and naturally, present together; for disease is the product of sin. It has been contended that demon-possession and lunacy are the same, but this scripture shatters that contention, as it differentiates between them.