My sister, who is a few weeks away from being a registered RN told the following story about a very Good Boy.
A patient with schizophrenia suffered from periodic hallucinations of people who weren't there. He got himself a service dog, and one of the service dog's chores was to go up and greet people on command.
So: if the dog went up to greet a person, the person was real. And if the dog did not greet a person when commanded, the person was a hallucination.
