Aggression. Overly aggressive behavior and uncontrolled bouts of anger can testify that the man was possessed by a demon. Unexplained irritability is becoming more frequent. The logical person stops to perceive their actions. The flash of hatred for everything around to make him commit acts of violence. He can hit a small child for a minor mistake, break the glass on the wall. Nervous breakdowns alternate the possessed with extreme apathy.
Seizures. Epileptic fits and seizures are a manifestation of demonic possession. No this man who was totally calm, in a moment begins to convulse. It is so unnatural to bend that leads around in horror. Everything can be blamed on the individual flexibility of the spine, but it is not the only explanation.
Loss of contact with reality. Demon possession is manifested in the strange behaviour of people, who behaved absolutely adequately. They hear voices, they see things can not see the other. It's like schizophrenia, but may be occult.
Apathy. When the demon more and more rooted in the human body, the latter falls into a lethargic state. It is idle, cease to go to work, chat with friends. Then it could turn into a suicidal state. Possessed seeks to take his own life. Usually he tries to implement it through the piercing and cutting items. There is something sacred. So the demon finally seeks to weaken the will of the possessed.
The knowledge of languages. If the previous reasons can be explained from the point of view of psychology, then it is obviously paranormal activity. The man, who has not owned and two languages, suddenly starts to talk in a few. Most often these are dead languages, like Latin or ancient Sumerian. The voice of the possessed may change beyond recognition. He goes to cry, a gasp, a roar sounds from far away. Often a person might be possessed by not one, but multiple demons, so they speak different languages.
Language. The presence of speech possessed of obscenities and vulgarity is an integral sign of possession. In General, the person becomes vulgar and behaving indecently. His sexual attacks on other people can be unnecessarily provocative. Obscenity is usually one of the last criteria before the full indwelling of the demon and the displacement of human personality.
The denial of religion. In the initial stages of obsession people have a negative attitude to all religion symbols: crosses, Bibles, Holy water. But on the last time the demon so strengthened his power, that he begins to do sacrilege on them. Obsessed spits on crosses, Holy water on him does not work.
Soreness. At the last stage of introduction of the demon man looks very painful. His skin has a greenish-gray hue. The eyes become red and watery. He was constantly sick, he's aching joints. He stops eating and his organs gradually begin to decline. The seizures and weakening of the body lead to death.