I don't know if this is possible but I'm sure this phenomenon is common and people aren't aware of any of it... there can be a lot of ideas that can be logical, I'm intuitive and I've had dreams about dead people not knowing they're dead, mainly it's people I've met or been around like living in a house where someone has died or visiting a house..
There aren't any reasonable and justifiable reasons as to why I believe that I've experienced or been experiencing psychic invasions or Astral intrusion, when I was younger I used to dream that I'd leave my body and climb on the ceiling and be stuck.. that ended..
I've been hearing voices of multiple people and demons or whatever you would call them, but negative intrusive things that invade my mind and in dreams I hear them clearly, I call it the devil voice, anyway I've tried going to a church, I've tried having a cleansing I've said prayer countless times. The voice in Satan's voice says I can give you everything you want and you'd want for nothing... then it uses voices of people who I've only seen, it uses the voice of someone I cared about..
I think this isn't schizophrenia but I could be wrong, maybe I'm not hearing demons and there's no Astral plane.. I don't know but I'd like to give cleansing a try and also talk with someone who could help me... I'd like to know how to prevent this when sage or church doesn't keep this at bay.