Earliest Reference: The earliest reference to the concept of demonic possession is found in the ancient Sumerian Civilization that originated in southern Mesopotamia. The Sumerians maintained that all sorts of diseases were caused to human beings by the 'gidim' or sickness-demons.
What is a Demon?: Many popular cultures believe that a demon is a supernatural, diabolic and often destructive entity who takes pleasure in causing harm to human beings in varied ways. Although the concept of demonic possession is found in several religions, the details and descriptions vary significantly.
Symptoms of Demonic Possession: The symptoms or signs of a person's being possessed by demons are trembling, frequent vomiting, sudden faints, access to unknown spiritual knowledge, knowing of foreign languages, speaking in a strange and often dreadful, fearsome voice, injuries all over the body, possession of more physical strength than is humanly possible and even a changed facial appearance.
Suggested Religious Treatments: All cultures and religions agree that exorcism is the only way of getting rid of a demonic possession. However, the methodology of performing this exorcism to get rid of the demonic possession varies greatly. Different religions suggest different methods of performing an exorcism, including performance of rituals with offerings to please the demon, praying to God to expel the invading demon from the person's body, compelling the demon to leave the victim's body by asking the good spirits for assistance and the use of incantations, special enchanted objects like holy water, ash, etc. to scare away the demon.