In the case of Rock v. Arkansas, 1986, the U.S. Supreme Court ruled that a blanket ban on hypnotically refreshed testimony was unconstitutional as it violated a defendant's right to testify in their own defense under the Fourteenth Amendment's due process clause and Sixth Amendment’s compulsory process clause. The case involved Vickie Lorene Rock who had been charged with manslaughter for shooting her husband. She could not remember all details about the incident so she underwent hypnosis to refresh her memory before trial. The court held that while states have legitimate interests in barring unreliable evidence, they cannot do so by categorically excluding such testimony without considering its reliability in individual cases.

In the dissenting opinion for Rock v. Arkansas, Justice Blackmun argued that the majority's decision to allow hypnotically refreshed testimony was a mistake due to its potential unreliability. He pointed out that there is significant scientific disagreement about whether hypnosis can reliably enhance memory recall and expressed concern about the risk of suggestion influencing such testimonies. Furthermore, he noted that even if some valid memories could be retrieved through hypnosis, it would be impossible for courts to distinguish between these and false or suggested memories. Therefore, he believed it would have been more prudent for the court to err on the side of caution by excluding all hypnotically refreshed testimony until further research could establish its reliability beyond doubt.