Jenkins v. United States

307 F.2d 637
Brief Filed: 2/62
Court: United States Court of Appeals for the D.C. Circuit
Year of Decision: 1962

Read the full-text amicus brief (PDF, 200KB)


Whether a psychologist is competent to state professional opinions as an expert witness concerning the nature, and existence or non-existence, of mental disease and defect

Index Topic

Expert Witnesses/Psychologists' Competency, Insanity Defense


In a trial for housebreaking, assault and intent to rape, a defendant presented the testimony of three clinical psychologists in support of an insanity defense. All three psychologists testified, based on their personal contact with the defendant, review of his case history and standard psychological tests, that on the date the alleged crimes were committed, defendant had been suffering from schizophrenia. One of the three testified that he could give no opinion concerning the relationship between the illness and the crimes but the other two gave opinions that the two were related and that the crimes were the product of the illness. At the conclusion of the trial, the judge instructed the jury to disregard the opinions of the psychologists in that psychologists were not qualified to give expert testimony on the issue of mental disease. On appeal, the D.C. Circuit reversed and remanded, and held that psychologists were qualified as expert witnesses on the question of mental disease.

APA's Position

APA submitted an amicus brief arguing that: (1) psychology is an established science; (2) the practice of psychology is a learned profession; (3) a clinical psychologist is competent to express professional opinions concerning the existence or non-existence of mental disease or defect and their causal relationship to overt behavior; and (4) experience is the essential legal ingredient of competence to give an expert opinion.


The D.C. Circuit reversed the conviction and remanded for a new trial. On the issue of psychologists' expert testimony, the court stated that some psychologists are qualified to render expert testimony on mental disorders. The court further stated that the determination of a psychologist's competence to render an expert opinion based on his findings as to the presence or absence of mental disease or defect must depend upon the nature and extent of his knowledge and not simply on the claim to the title "psychologist."