There are many cultures and religions that still believe in demonic possession. While I don’t believe that a ghost could possess someone’s body, I do think that they can influence someone’s behavior without that person realizing it. Demonic possession is different; theoretically demons are not the same as ghosts because they have never been born into a body. Today the Catholic Church still believes in demonic possession and even has priests that specialize in exorcisms to deal with this problem.
Demon possession is relatively rare; many cases are actually mental health issues, but for those rare cases that are real, there are a few signs to look for, such as change in personality and mental state. A person may become more aggressive or withdrawn, with a tendency toward violence. The person that is possessed may begin to have terrible nightmares and speak in a language that they do not know.
Another sign of demonic possession could be the person’s ability to tell future events or know about events in the past that they would have no way of knowing about.
