(concurring).
I concur in the remand because the court’s basic holding that a psychologist is not barred as a matter of law from giving expert testimony about mental ■ diseases makes it essential that we have a comprehensive record before us on the education and training of psychologists in general and clinical psychologists in particular. This is emphasized by recalling that appellant’s entire case in this court, including his oral argument, was based on matter outside the record in the form of recitals of what various writers thought on the subject of whether, and to what extent, psychologists should be permitted to testify relating to mental disease. Similarly the majority opinion relies largely on “the literature.” The literature cited and relied on by the appellant, and indeed by the majority opinion originally, was.and is now a series of references selected to support one or the other point of view. They were not developed in the record by an adversary process or subjected to adversary examination. The reason we now remand is to have a record made in an orderly way and in that process authoritative texts, or parts thereof, may well be offered and received, subject, of course, to the established rules of evidence.
At the outset certain factors should be kept in mind. The issue is not now and never was whether a psychologist’s testimony is admissible in litigation where “sanity” is in issue. Such testimony has long been admissible in the form of psychological tests and the analysis and explanation of such tests by a psychologist. No one doubts that such matter is admissible. The real issue in dispute is whether the clinical psychologists in this case, by which we mean persons having degrees of Doctor of Philosophy in Psychology, and also additional training as clinical psychologists, are competent in a scientific sense and hence legally qualified
(1) to make a diagnosis of the existence and character of a mental disease, and
(2) whether there is a causal relationship between a disease and an unlawful act.
The issue can be stated also in terms of whether medical opinions and medical *648diagnoses can be made by and be the subject of expert testimony by a Doctor of Philosophy in Psychology with added clinical experience. For convenience I will hereafter refer to such a psychologist as a Clinical Psychologist.
While the issue is new to this court it is not new to medicine and psychiatry. In 1954 a Resolution was adopted by the American Medical Association, the Council of the American Psychiatric Association and the Executive Council of the American Psychoanalytical Association to the effect that psychologists and other related professional groups were autonomous and independent in matters where medical questions were not involved, but that where diagnosis and treatment of mental illness was involved the participation of psychologists “must be co-ordi-nated under medical responsibility.”1 This Resolution, while not controlling on the courts is plainly entitled to great weight.
My difficulty with the opinion of the majority, as distinguished from the remand for additional evidence, is that it fails to give adequate guidance as to the scope and nature of the inquiry to be conducted by the trial judge on remand. I agree that it is entirely within the discretion of the District Court whether he should conduct the hearing out of the presence of the jury. In this particular *649case, since this is an exploratory process, there are probably valid practical reasons to hold the hearing out of the presence of the jury although once we resolve the basic problem, that process would not be necessary in future cases.
As I see it, the hearing to be conducted in this case will be somewhat unusual because of the nature of the question and the need for a comprehensive record of testimony. The practical reason for conducting this particular hearing out of the presence of the jury is that the hearing could well take several days. It is not a question which can be resolved simply by examination of the particular psychologists whose testimony is offered. The preliminary hearing on qualifications will be enlarged if the District Judge allows, as he might well do, participation by the several amici curiae, who are highly qualified to be of aid to the court. That would be a dubious process for every future case but entirely appropriate for this case. We have said that the conduct of the hearing lies in the sound discretion of the trial judge. But it is not enough to say that it is within the sound discretion of the trial judge and at the same time fail to reflect just what we are driving at.
We must bear in mind that there is a difference between the holdings “that some psychologists are qualified to render expert testimony in the field of mental disorder” (see note 14 majority opinion) and the question of a psychologist’s competence to make a diagnosis of mental disease. The former proposition is, as we have noted, widely accepted; the latter is not — and it is the latter we are now exploring.
On remand I assume broad areas are to be explored and should be explored in order to give the trial judge, in the first instance, and this court if need be, an evidentiary basis and a record on which to act. As I see it, the remand hearing ought to cover among other things the following:
(a) The scope, nature and extent of the education of a Ph.D. in Psychology and in Clinical Psychology, including time spent in hospitals, with patients, and under what supervision.
(1) What is the education, training and clinical experience of the proffered witness?
(2) Define for the record the term “clinical experience.”
(b) What, in particular, is the extent and scope of this Clinical Psychologist’s clinical education in physiological and medical subjects? How does it compare with that of a psychiatrist?
(c) What is the scope of the work of Clinical Psychologists at St. Elizabeths Hospital I2
(1) Do they make diagnosis of mental diseases on their own independent responsibility or only subject to the supervision of a psychiatrist ? The relationship should be developed fully.
(2) What is the scope of the work and extent of clinical responsibility of the particular Clinical Psychologist with patients independent of psychiatrists ? That is, what work is done fully by' the Clinical Psychologist alone and without regard to any supervision or overseeing by a psychiatrist ?
(d) In how many specific cases has the particular Clinical Psychologist made a diagnosis of mental disease, prescribed or supervised treatment of patients without the *650intervention or approval of a psychiatrist ?
(e) In how many cases approximately (whether at St. Elizabeths or elsewhere) has the witness made a diagnosis of the existence or nonexistence of mental disease and communicated that diagnosis directly to the patient or patient’s family independent of a psychiatrist?
(f) To what extent has the witness prescribed or supervised treatment of mental patients independent of a psychiatrist?
(g) The opinions of both psychiatrists and clinical psychologists ought to be made part of the record on the following:
(1) In what kinds or categories of mental disease are the physiological and medical factors not of any consequence ?
(2) In what categories does a diagnosis of mental disease involve analysis, understanding and synthesis of physical and physiological factors as well as psychological factors ?
(3) If diagnosis of mental disease always involves consideration of or evaluation of physical, biological or physiological data, how does a clinical psychologist acquire clinical experience and scientific competence to make such diagnosis?
(4) What is a differential diagnosis in the context of diagnosis of mental disease?
(5) Is the process of diagnosis of mental disease the elimination of various alternative explanations?
(6). In this process what factors must be taken into account ?
(7) In the process of eliminating alternative explanations do the medical history of the patient, the physical examination and various medical tests play a part?
(8) Can any mental disease .be diagnosed without taking into account pathological data? If so, what mental diseases can be diagnosed independent of and without regard to pathological data?
The cases cited by the majority concerning the optometrist, the toxicologist and other skilled specialists who are not medical doctors are not in any real sense relevant. Indeed they tend to divert us from the central issue. Of course an optometrist or the toxicologist is permitted to give some expert testimony within his competence just as a skilled shoemaker might be qualified to testify from long observation and experience as to the effect of wearing certain kinds of shoes, or a farrier to give expert testimony about the effect of certain types of shoeing on horses.
The heart of our problem is not whether a clinical psychologist is qualified to testify as an expert, for of course he is in some areas, but whether he is qualified to give expert testimony in the form of a diagnosis of a mental disease or illness, and to express an opinion on whether a stated mental disease “caused” the patient to commit a given unlawful act or “produced” that act. More rationally the question ought to be whether mental disease so substantially affected him that he was unable to control his conduct.
I agree with the majority that the scope of the training of the psychologist is of critical importance and that many factors other than academic degrees go to the admissibility and weight of the expert testimony. For example, if a general medical practitioner testified on the subject of mental disease, and gave a diagnosis of presence or absence of mental illness in opposition to a trained psychia*651trist it would obviously be proper for the trial judge to tell the jury they could take into account the differences in training and experience in weighing the testimony of the one against the other. In the same way it would be proper, if a clinical psychologist is found qualified to testify as to the presence or absence of a mental disease and does so in opposition to a psychiatrist, to tell the jury they could take into account the difference in the education, training and experience of psychologists and psychiatrists and the absence of medical training in the former.
. The Resolution in full is as follows:
“For centuries the Western world has placed on the medical profession responsibility for the diagnosis and treatment of illness. Medical practice acts have been designed to protect the public from unqualified practitioners and to define the special responsibilities assumed by those who practice the healing art, for much harm may he done by unqualified persons, however good their intentions may be. To do justice to the patient requires the capacity to make a diagnosis and to prescribe appropriate treatment. Diagnosis often requires the ability to compare and contrast various diseases and disorders that have similar symptoms but different causes. Diagnosis is a continuing process, for the character of the illness changes with its treatment or with the passage of time, and that treatment which is appropriate may change accordingly.
“Recognized medical training today involves, as a minimum, graduation from an approval [sic] medical school and internship in a hospital. Most physicians today receive additional medical training, and specialization requries [sic] still further training.
“Psychiatry is the medical specialty concerned with illness that has chiefly mental symptoms. The psychiatrist is also concerned with mental causes of physical illness, for we have come to recognize that physical symptoms may have mental causes just as mental symptoms may have physical causes. The psychiatrist, with or without consultation with other physicians, must select from the many different methods of treatment at his disposal those methods that- he considers appropriate to the particular patient. His treatment may be medicinal or surgical, physical (as electroshock) or psychological. The systematic application of the methods of psychological medicine to the treatment of illness, particularly as these methods involved gaining an understanding of the emotional state of the patient and aiding him to understand himself, is called psychotherapy. This special form of medical treatment may be highly developed, but it remains simply one of the possible methods of treatment to be selected for use according to medical criteria for use when it is indicated. Psychotherapy is a form of medical treatment and does not form the basis for a separate profession.
“Other professional groups such as psychologists, teachers, ministers, lawyers, social workers, and vocational counselors, of course, use psychological understanding in carrying out their professional functions. Members of these professional groups are not thereby practicing medicine. The application of psychological methods to the treatment of illness is a medical function. Any physician may utilize the skills of others in his professional work, but he remains responsible, legally and morally, for the diagnosis and for the treatment of his patient.
“The medical profession fully endorses the appropriate utilization of the skills of psychologists, social workers, and other professional personnel in contributing roles in settings directly supervised by physicians. It further recognizes that these professions are entirely independent and autonomous tvhen medical questions are not involved; but when members of these professions contribute to the diagnosis and treatment of illness, their professional contributions must he co-ordinat-ed under medical responsibility.” (Emphasis added.)
. In this connection an obviously well qualified expert, who might well be called as a witness by the court, if he is not called by any party, is the Superintendent of St. Elizabeths Hospital who has presided over a staff of psychiatrists and clinical psychologists dealing with precisely the issues of criminal responsibility.