In Buchanan v. Kentucky, the U.S Supreme Court ruled in 1986 that a defendant's statements made during a court-ordered psychiatric examination could be used by the prosecution at trial if the defendant had not been warned about his right to remain silent under Miranda rights. The case involved Jeffrey Leonard Buchanan who was charged with murder and robbery. His defense counsel requested for a mental evaluation which revealed incriminating evidence against him but he wasn't informed of his Miranda rights before this evaluation took place. The court held that since it was the defense team that initiated the request for an examination, they essentially waived their client’s Fifth Amendment privilege against self-incrimination and therefore, there was no violation of Buchanan's constitutional rights when these statements were admitted into evidence at trial.

In the dissenting opinion for Buchanan v. Kentucky, Justice Brennan argued that the admission of a psychiatrist's testimony violated the defendant's Sixth Amendment right to confront witnesses against him. He contended that since the psychiatrist had not personally examined Buchanan but instead relied on reports from other psychiatrists who did, those reports were hearsay and should have been excluded from evidence. Furthermore, he believed this case was different than previous cases where such testimonies were allowed because in those instances, defendants introduced psychiatric evidence first or requested mental examinations themselves. In contrast, Buchanan neither initiated nor consented to any psychiatric examination; thus his rights under both Fifth and Sixth Amendments were infringed upon by admitting such testimonies without giving him an opportunity to cross-examine all involved parties.