Rosenhan himself and other eight pseudo patients who were mentally healthy claimed that they had auditory illusions and they were admitted in the hospital.
They were diagnosed that they were the patients of schizophrenia and they were debased. They were also diagnosed that they had manic depressive lunacy and they needed to be in a mental asylum. After the diagnosis, they claimed that they were fine and they desired to go out of the hospital.
The impact of this diagnosis is that Rosenhan condemned the dependability of the psychiatric analysis. He uncovered the truth in the experiment rather than the methodology of the experiment.