Mental Illness: If you or someone you know is expressing that something is wrong with their mind or feels that they have a disorder or imbalance of the mind. 

The Word of God promises Christians a sound mind. Mental illness is a part of the curse of the law and is often a result of sin and disobedience to God(Deut. 28:15-28). Sometimes demonic activity is involved(Matt. 17:14,21), or possibly actual physiological damage.