From June 2018 Harpers by  T.M. Luhrmann, via 3 Quarks  Daily

In 1973, David Rosenhan, a professor of psychology at Stanford,….persuaded seven friends to join him in an experiment. He asked them to make appointments at multiple psychiatric hospitals across the country and explain to the doctors that they had heard voices that said things like “empty,” “hollow,” and “thud.” Apart from their names and professions, they were to change no details about their lives. Each participant was admitted as an inpatient to a psychiatric ward, and in every case but one they were diagnosed with schizophrenia. Doctors released them after, on average, nineteen days, but one was held for nearly two months. “It is clear,” Rosenhan wrote, “that we cannot distinguish the sane from the insane in psychiatric hospitals.”….

….Self-report measures find that they work. That is, the methods make hearing voices less aggravating for most people, and some find that their voices become kinder, softer, or even go away. In the United Kingdom and the Netherlands, Hearing Voices groups have become almost mainstream, and many European clinicians have abandoned the oversimplified biomedical approach that treats voices as irrational byproducts of a disordered brain.

For a lot more info from the original article in Harpers June 2018 see Harpers pr 3Quarks Daily