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 at the time of the offense the defendant, as a result of a mental disease or defect, did not understand the wrongfulness of his conduct.

Places the burden of proof of insanity on the defendant.

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

Amends the Federal Rules of Evidence to prohibit expert witnesses from offering opinions on the issue of the insanity of the defendant.

Provides for an initial screening examination to determine whether there is reasonable cause to believe that the defendant lacks competence. Allows for a more thorough examination of the defendant if the initial results suggest incompetence. Requires a hearing on the issue of competence and further examination on the issue of the likelihood of the defendant's recovery. Allows for appropriate treatment if necessary. Requires in-patient treatment only when the defendant is dangerous, likely to flee, or in custody.

Transfers to State officials for State civil commitment certain defendants who have received the maximum treatment under this section or are found incompetent with no substantial probability of improvement.

Allows a person serving a sentence of imprisonment to be transferred to a mental institution upon a showing of clear and convincing evidence that the prisoner is in need of treatment.

Establishes Federal commitment procedures for persons found "not guilty only by reason of insanity". Provides for a special examination of violent offenders in order to determine their dangerousness.

Requires a board of examiners for every Federal penal and correctional institution which shall examine prisoners about whom there is probable cause to believe competence at trial was lacking even though the issue was not raised and determined. Requires the district court concerned to vacate conviction and order a new trial for any prisoner about whom such a board certifies that such probable cause does exist.