Insanity Defense Reform Act of 1983 - Amends the Federal criminal code to make it an affirmative defense to a Federal prosecution that the defendant, as a result of severe mental disease or defect, could not at the time the offense was committed appreciate the wrongfulness of his conduct or conform his conduct to the requirements of law. Places the burden of proving the defense of insanity on the defendant. Prohibits expert witnesses from offering opinions on the ultimate legal issues presented to the trier of fact.

Authorizes a special verdict of "not guilty by reason of insanity" for any criminal defendant who raises the issue of insanity by notice as provided by Rule 12 of the Federal Rules of Criminal Procedure.

Requires the court to hold a hearing to determine the present mental condition of a defendant found not guilty on such ground. Directs the court to commit such person to the custody of the Attorney General upon a finding that the person's release would create a substantial risk of bodily injury to another as a result of his present mental disease or defect. Directs the Attorney General to release such person to the State or to hospitalize such person in a suitable facility.

Provides that when the defendant has recovered and would no longer create a substantial risk of bodily injury, the court on the motion of the attorney for the Government or on its own motion shall hold a hearing to determine if such person shall be released or conditionally discharged. Allows for the revocation of any conditional discharge.