No I don't believe anyone has been demons possessed, since Christ defeated the Devil and His Demons 2000 years ago. We don't have a single recorded instance since that time.So you dont believe in instances of demon possession in todays world?
Mark 16:17-18
17 And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
18 They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.../KJV
WHat do we do with this passage?
If a Demon desires to possess someone, He must first ask Jesus for permission to possess that person. I don't believe Jesus would allow any Demon to possess anyone. Unbelievers are already possessed by the spirit of unbelief, which we inherited from father Adam.
When a person is regenerated and born again, he is possessed by a new Spirit, the Holy Spirit and the only way a Demon could possess a Christians is to coinhabit the person with the Holy Spirit. And that's impossible, and so Demon possession is impossible.
Mark 16:17-18 was speaking of the Disciples, because nobody else was given the gift of casting out devils or to speak in tongues after them. I've never heard of someone speaking a foreign language without first learning the language but the Disciples did.
The Disciples were also given the gift of immunity from snake venom and poison, and the power to heal the sick. These things were temporary gifts, they only had them until they fulfilled their purpose of taking the gospel int0o the known world and then they were all executed like Christ. John was the only one who was spared.