I have mild schizophrenia and yes, I do hear voices. Mostly benign, and not one of them says "thud." But this is why I'm hesitant to go to a doctor/therapist. I do not want to be drug-addled, at all. As you read, it's so easy to get the medication, just by having a voice say "thud." I say, talk to the voices, agree to get along, and go on with your life.