(a) Affirmative Defense.–It is an affirmative defense to a prosecution under any Federal statute that, at the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts. Mental disease or defect does not otherwise constitute a defense.

Terms Used In 18 USC 17

  • Defendant: In a civil suit, the person complained against; in a criminal case, the person accused of the crime.
  • Evidence: Information presented in testimony or in documents that is used to persuade the fact finder (judge or jury) to decide the case for one side or the other.
  • Statute: A law passed by a legislature.

(b) Burden of Proof.–The defendant has the burden of proving the defense of insanity by clear and convincing evidence.