A bill to modify the insanity defense in the Federal courts, and for other purposes.

Amends the Federal criminal code to make it a defense to a Federal prosecution that the defendant, as a result of mental disease or defect, lacked substantial capacity to appreciate the criminality of his conduct. Places the burden of providing insanity on the defendant.

Authorizes a special verdict of "not guilty by reason of insanity."

Prohibits witnesses from offering opinions on whether the defendant lacked substantial capacity to appreciate the criminality of his conduct.