A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law. The terms "mental disease or defect" do not include an abnormality manifested only by repeated criminal or otherwise antisocial conduct.
Defendant unsuccessfully asserted an insanity defense in his trial for bank robbery under 18 U.S.C.S. § 2113. On appeal, the court reversed defendant's conviction because it rejected the definition of insanity under which complete lack of mental capacity was required and adopted a definition of substantial lack of capacity. The court held that because defendant was able to have understood the proceedings against him and cooperated in his own defense, due process was not violated by his pretrial incarceration. The court held that the instructions as to burden of proof were correct because some evidence of insanity required submission of the issue to the jury but the issue of sufficiency of evidence necessary to have created a jury issue was for the judge. The court held that reasonable men would not have necessarily had reasonable doubt as to defendant's sanity, so no judgement of acquittal was required.
Did the district court err in its failure to admit defendant's defense of mental insanity?
The court reversed the verdict because the definition of insanity that required complete lack of mental capacity, charged by the lower court, was rejected in favor of a definition that enabled application of modern knowledge about mental diseases, under which a substantial lack of capacity was required. The court thus adopted the Model Penal Code definition that had been adopted by other circuits.