Does the Bible promise that Christians will be delivered from mental illness of all kinds?
First of all, let me say that God CAN deliver from all sorts of mental illness. With that said, it is important to know that the Lord does not promise to deliver us from mental illness, or any illness that we might have.
There are so many types of mental illness, from depression, to schizophrenia, to paranoia, to bipolar, etc. Some are caused from abnormalities in the brain, while some may be caused as a result of drugs or alcohol. Some we are born with, some being self-inflicted. Some mental disorders can be caused by trauma to the head. And then, sometimes if we harbor anger, bitterness, unforgiveness, hatred, etc. these things can certainly affect our mental state.
It is possible that one who has been diagnosed as mentally ill really is possessed by a demon or demons. We read in Luke 11:14, “And he was casting out a devil, and it was dumb. And it came to pass, when the devil was gone out, the dumb spake; and the people wondered.” We also read in Luke 8:27-33, “And when he went forth to land, there met him out of the city a certain man, which had devils long time, and ware no clothes, neither abode in any house, but in the tombs. When he saw Jesus, he cried out, and fell down before him, and with a loud voice said, What have I to do with thee, Jesus, thou Son of God most high? I beseech thee, torment me not. (For he had commanded the unclean spirit to come out of the man. For oftentimes it had caught him: and he was kept bound with chains and in fetters; and he brake the bands, and was driven of the devil into the wilderness.) And Jesus asked him, saying, What is thy name? And he said, Legion: because many devils were entered into him. And they besought him that he would not command them to go out into the deep. And there was there an herd of many swine feeding on the mountain: and they besought him that he would suffer them to enter into them. And he suffered them. Then went the devils out of the man, and entered into the swine: and the herd ran violently down a steep place into the lake, and were choked.” These people who were possessed by demons were surely thought to be insane by those around them, however theirs was a spiritual problem, not a mental problem.
In one instance, the Lord took away a king’s ability to function normally because of his pride and unbelief. We read in Daniel 4:30-32, “The king spake, and said, Is not this great Babylon, that I have built for the house of the kingdom by the might of my power, and for the honour of my majesty? 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. And they shall drive thee from men, and thy dwelling shall be with the beasts of the field: they shall make thee to eat grass as oxen, and seven times shall pass over thee, until thou know that the most High ruleth in the kingdom of men, and giveth it to whomsoever he will.”
Whatever the cause of mental disabilities, how should we, as believers, treat those who suffer such illnesses? We should be sympathetic and pray for them even as we pray for those who are physically ill. James 5:16 tells us to, “Confess your faults one to another, and pray one for another, that ye may be healed. THE EFFECTUAL FERVENT PRAYER of a righteous man availeth much.” Because of our sincere and fervent prayers, the Lord may see fit to heal one who suffers from mental problems. He could do that through His mighty touch, or by using the knowledge given to man to treat such illnesses. The Lord has allowed men to develop great knowledge about our bodies and brains. Realizing that, we can surely turn to physicians for help. The writer of the Gospel of Luke and the book of Acts was a doctor. We read in Colossians 4:14 of, “Luke, the beloved physician…”
It could be that the Lord will allow us to suffer from mental disabilities in order to teach and strengthen us. In order to keep Paul humble after all the revelations the Lord had given him, the Lord gave him a “thorn in the flesh.” We read in 2 Corinthians 12:7-9, “And lest I should be exalted above measure through the abundance of the revelations, there was given to me a thorn in the flesh, the messenger of Satan to buffet me, lest I should be exalted above measure. For this thing I besought the Lord thrice, that it might depart from me. And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities, that the power of Christ may rest upon me.” After praying for healing three times, Paul realized his lesson was to realize that He had the Lord’s grace…and that was all he needed. (CC) (625.6)