It can happen that a normally functioning person may suddenly, from one hour to the next, stop knowing who they are, what they're saying, what they're doing; they see visions, they hear voices. They can sense that they're being touched, forced to do things, they feel compulsions. They may notice scratches or wounds on their bodies and not know where they've come from. They may be aware of the moment the injury occurred, see the blood flowing, and feel pain even though they are far from any sharp objects. A person who till then had been active, sociable, cheerful may suddenly become closed in on themselves, it may be hard to make contact with them, they themselves may start to have suicidal thoughts. Or vice versa: a calm person may become aggressive, ready to destroy everything in one moment, sometimes even to kill someone. Their eyes emanate hatred even towards those they'd loved till now. A refined person may suddenly become vulgar, swearing at people for no reason - in a streetcar, a shop, a church or the street. They may smell some scent everywhere, anything from a pleasant one to a terrible odor. Or vice versa, people around them may smell an unpleasant stench coming from the person, even though that person may wash constantly.
I mentioned earlier that there can be many ghosts residing within one person. Each one of them will have a completely different character, a different approach to various matters, a different assessment of reality. One of them may, in a given situation, switch on fear, another one may withdraw or become aggressive and create an argument. Another one still may not react at all, treating the matter with stoic calm or indifference. The person's character will depend on which ghost is at the wheel of the possessed person's mind. From the outside this will be perceived as constantly mood swings. When there are many ghosts present, the people around the possessed person never know what to expect. One time a dish will taste good to them, another time they will throw the plate against a wall with disgust, or one time they may like to go to the opera or a piano recital and another time they'll cover their ears at the very sound of music. One time they may like to play some game and be very good at it, playing it like a champion, another time they don't even know the game's rules. One time they may paint, write or sing brilliantly, another time they'll make a mess and sing off-key. One time they'll have perfect vision, another time they'll need to wear glasses. I could give many more examples but by now you've probably realized what I'm talking about - mood swings. When ghosts enter a person then their problems become that person's problems. When they are led away, suddenly everything returns to normal, including moods and competencies.