Contrary to uninformed opinion, defendants who are found not guilty by the reason of insanity are not merely released from the custody. They are usually committed into mental hospitals where they are confined for duration longer than their prison terms would have been. For example in the case of Jones v. United States, the Supreme Court in 1983 backed this proposition, ruling that the sentence that criminal defendants should have received had they been convicted shall have no bearing on how long they could be committed to a mental hospital.
Therefore the correct answer to fill in the blank is “may be longer”.
