United States v. Lyons: Toward a New Conception of Legal

of legal insanity to conform with recent recommendations of the American Bar Association and the American Psychiatric Association. This paper briefly reviews the social and legal context of the Court's ruling. The author then discusses the insanity defense's rationale and suggests an interpretation of the Court's new defi-nition that should guide psychiatric testimony. John Hinckley, Jr. 's, 1982 insanity ac-quittal provoked widespread shock, outrage, and calls for legal reform. By contrast, United States v. Lyons, ' a 1984 decision that brought actual changes in the U.S. Fifth Circuit's defi-nition of insanity, has attracted scant attention. Robert Lyons was convicted in Lou-isiana on several counts of securing controlled narcotics. He appealed, ar-guing that, when he was originally tried, he should have been allowed to have experts testify that involuntary addic-tion and brain damage had caused a vo-litional impairment that left him unable to resist obtaining and using drugs. The U.S. Fifth Court of Appeals reheard the case en banc and agreed that expert tes-timony should have been permitted. Dr. Mossman is an instructor in the Department of Psy