Editing Mark David Chapman (section)

==== Mental state assessment ====
More than a dozen psychologists and psychiatrists interviewed Chapman in the six months prior to his trial—three for the prosecution, six for the defense, and several more on behalf of the court—and they conducted a battery of standard diagnostic procedures and more than 200 hours of clinical interviews. All six defense experts concluded that Chapman was psychotic; five diagnosed paranoid schizophrenia, while the sixth felt that his symptoms were more consistent with manic depression. The three prosecution experts declared that his delusions fell short of psychosis and instead diagnosed various personality disorders. The court-appointed experts concurred with the prosecution's examiners that he was delusional yet competent to stand trial. In the examinations, Chapman was more cooperative with the prosecution's mental health experts than with those for the defense; one psychiatrist conjectured that he did not wish to be considered "crazy" and was persuaded that the defense experts only declared him insane because they were hired to do so.

Charles McGowan had been pastor of Chapman's church in Decatur, Georgia, and he visited Chapman. "I believe there was a demonic power at work," he said. Chapman initially embraced his old religion with new fervor as a result; but McGowan revealed information to the press that Chapman had told him in confidence, so Chapman disavowed his renewed interest in Christianity and reverted to his initial explanation: he had killed Lennon to promote the reading of ''The Catcher in the Rye''.