UNITED STATES CODE
Title 18
Crimes and Criminal Procedure
§ 17. Insanity defense
(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.
(b) Burden of Proof. - The defendant has the
burden of proving the defense of insanity by clear and convincing
evidence.