The subject of mental illness is very controversial in Christian circles. Inside the extreme schools of thought, we find balance and a scriptural viewpoint.

First, let me say clearly: All mental illness is not the result of demonic attack. Further, good psychological care from Christian professionals is vital and in order when an individual is struggling.

Also, professionally administered medication may be necessary when chemical imbalances occur. But when normal medicine and therapy do not result in a cure, then it is possible that these symptoms could point to demonic operation.

Let me list for you 14 symptoms of demonic operation. As these symptoms are listed, realize that some of them could also be caused by something other than demonic oppression. The first six symptoms on this list are extreme and are drawn from the account of the demoniac of Gadara in Mark 5. This man had been chained in a cemetery because of his erratic and violent behavior. When you look at Mark 5:1-15, you can see clear symptoms of demonic activity.

Symptom 1: Incapacity for normal living (Mark 5:1-5)
Just as the actions of Legion made the man unsuitable for normal social interaction with friends and family, an unusual desire for solitude, accompanied by a deep loneliness, will often set in. The person will often become very passive with no desire to change.

Symptom 2: Extreme behavior (Mark 5:4)
Violence will often be evident in the victim’s life. An explosive temper and extreme, uncontrollable anger are dangerous behaviors that control the individual and the people who love him or her.

Symptom 3: Personality changes (Mark 5:9, 12)
Multiple personalities exist in some of the most serious cases of demonic control. This man had a “legion” of spirits within his life. All cases of multiple personality may not be demonic, but in most cases demon activity is involved. Changes in personality, extreme or mild, may be evidence of demonic activity.

Symptom 4: Restlessness and insomnia (Mark 5:5) 
In verse 5, we see this man crying in the tombs “night and day.” He could not sleep. Insomnia can be a sign of a physical problem or a sign of a spiritual problem. God has gifted His children with sleep (Ps. 127:2). So when you cannot sleep night after night and there is no medical reason for this disturbance, the devil maybe tormenting you. Don’t forget: You have the right to rest in Jesus!

In Psalm 3, we see a picture of warfare. Here David was hounded by his enemies. In verse 3, he cried to the Lord, “You ... are a shield for me.” In verses 5 and 6, he cried, “I lay down and slept; I awoke, for the Lord sustained me. I will not be afraid of ten thousands of people who have set themselves against me all around.” He also said in Psalm 4:8, “I will both lie down in peace, and sleep; for You alone, O Lord, make me dwell in safety.” Sleep is God’s gift to all who trust in Him.

Symptom 5: A terrible inner anguish (Mark 5:5)
This man was deeply tormented in mind and heart. Various levels of anguish are evident in those who are afflicted by demons. Grief and anguish are normal emotions for us all. Yet persistent, unresolved anguish that will not leave after normal therapies of counseling, encouragement and prayer could well be demonic.

Symptom 6: Self-inflicted injury and suicide (Mark 5:5)
Here we see the demonic man cutting himself. If you read Mark 9:14-29, you will see the story of the man whose son was both deaf and mute because of a demon: “Wherever it [the evil spirit] seizes him, it throws him down ... Often he [the demon] has thrown him [the boy] both into the fire and into the water to destroy him” (vv. 18, 22). Jesus cast out the demon: “The spirit cried out, convulsed him [the boy] greatly, and came out of him. And he became as one dead ... But Jesus took him by the hand and lifted him up, and he arose” (vv. 26-27). Demons can cause people to injure themselves. They even incite suicide.

Symptom 7: Unexplained illness with no obvious medical cause
When medical testing produces no physical cause for an illness, then we should look to the mind and spirit for answers. Sometimes illnesses are psychological, and good counseling can result in a cure. Other times the battle is with demons. A scriptural example of this is found in Luke 13:11-16, the story of a woman afflicted by a “spirit of infirmity” (v. 11). Jesus called her “a daughter of Abraham, whom Satan has bound” (v. 16). Obviously she was a child of God and faithful to her synagogue, with a desire to know more about the Lord. Then, “Jesus ... said to her, ‘Woman, you are loosed from your infirmity.’ And He laid His hands on her, and immediately she was made straight, and glorified God” (vv. 12-13). There are physical illnesses caused by a class of demons known as “spirits of infirmity.”

Symptom 8: Addictive behavior
Addiction to alcohol, drugs, sex, food, gambling and other things opens the door to demonic influence and control. I am not saying demons cause all of these problems; certainly people are responsible for their own wrong choices. But anything that causes one to be out of control opens that person to infernal control.

Symptom 9: Abnormal sexual behavior
When Jezebel’s son inquired about peace, Jehu responded, “What peace, as long as the harlotries of your mother Jezebel and her witchcraft are so many?” (2 Kings 9:22). In Ezekiel 16:20-51, the spirit of harlotry is mentioned several times. This spirit infected the nation of Israel with the sins of Sodom (vv. 49-50). They even sacrificed their own children (vv. 20-21).

Homosexuality, adultery, fornication and even infanticide are all inspired by the spirit of harlotry. Hosea 4:12 says, “The spirit of harlotry has caused them to stray, and they have played the harlot against their God.” Look at Hosea 5:4: “They do not direct their deeds toward turning to their God, for the spirit of harlotry is in their midst, and they do not know the Lord.”

A nation and a people given over to sexual sins and abominations is governed by this spirit of harlotry. Look at Nahum 3:4: “Because of the multitude of harlotries of the seductive harlot, the mistress of sorceries, who sells nations through her harlotries, and families through her sorceries.”

Nations and families are sold into spiritual bondage by the witchcraft of the spirit of harlotry. When we play around with sexual sin, we open ourselves to this demonic spirit. We must battle this principality that dominates our nation.

Symptom 10: Defeat, failure, and depression in the Christian life 
Paul wrote in 2 Corinthians 2:14, “Now thanks be to God who always leads us in triumph in Christ.” Notice this verse is preceded by an exhortation from Paul to forgive others “lest Satan should take advantage of us; for we are not ignorant of his devices” (vv. 10-11). It is Satan’s purpose to take advantage of our situations and to rob us of the victorious life that is ours in Christ. The psalmist cried out, “By this I know that You are well pleased with me, because my enemy does not triumph over me” (Ps. 41:11).

This symptom is often manifested by an inability to praise and worship. Psalm 92:1-4 is a testimony to the power of praise. It culminates in verse 4, where David said, “For You, Lord, have made me glad through Your work; I will triumph in the works of Your hands.” Again he said, “Save us, O Lord our God ... to give thanks ... [and] to triumph in Your praise” (Ps. 106:47).

Symptom 11: Occult involvement and behavior
Deuteronomy 18:9-12 catalogs the works of the occult and witchcraft, including child sacrifice; fortune-telling; soothsaying; interpreting omens; sorcery; and the work of those who conjure spells, mediums, spiritists and those who call up the dead. Then verse 15 instructs the people to hear the word of God from the prophet of God and order their lives accordingly. Occult involvement is clearly a symptom of demonic control.

Symptom 12: Speech difficulties
In Matthew 9:32-33, Jesus rebuked a demon, and the mute man was able to speak. Speech difficulties may be physical, emotional, mental and, in some cases, demonic. Extreme language and cursing may be prompted by the enemy.

Symptom 13: Doctrinal error
In 1 Timothy 4:1 we receive a warning that in the last days, deceiving spirits will teach the "doctrines of demons." Today, religious cults and charlatans abound. The reason these deceivers draw many people is the power of the demonic that teaches them.

Symptom 14: Religious legalism
Galatians 3:1 says to the believer who is in danger of going back under the Law, “Who has bewitched you that you should not obey the truth?” The church at Galatia had forsaken a faith ministry that resulted in the miraculous (v. 5) for a law ministry of rules and regulations. Paul classified this error as witchcraft.

Some deeply religious people are under the bondage of tradition, man-made rules and outward appearances. Demons thrive in this kind of environment, especially demons of control. It is a lot easier to keep a ritual or list of rules than it is to walk by faith. Wherever there is any substitute for faith in the finished work of Christ, it is a doctrine of demons.

Adapted from Demons & Spiritual Warfare by Ron Phillips, D.Min., copyright 2010, published by Charisma House. Since 1979, Phillips has been senior pastor of Central Baptist Church, now Abba’s House, near Chattanooga, Tenn. He hosts a daily online radio program, CenterPoint, and is the author of more than 20 books, including Our Invisible Allies (Charisma House).

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