Prior to his trial for shooting at a motor vehicle and assault with a firearm, a competency hearing pursuant to Penal Code section 1368 was held. Appellant was found competent to stand trial. At his subsequent trial, the prosecutor impeached appellant’s testimony with statements made during the competency exams by the court appointed mental health professionals. The trial court admitted the statements over defense objection. Appellant was convicted, and the appellate court affirmed. The California Supreme Court granted review to determine whether a testifying defendant may be impeached at trial with statements made before trial to mental health professionals during a court-ordered examination to determine competency to stand trial. The Court concluded that such impeachment violates the federal Constitution’s privilege against self-incrimination. However, given the overwhelming evidence of appellant’s guilt and the insignificant nature of the statements used at trial, the error here was not prejudicial.