The issues on this appeal under the provisions of G. L. c. 278, §§ 33A-33G-, as amended, relate to the defence of insanity. The defendant, McHoul, was convicted and sentenced for two crimes committed about 2 p.m. on March 29,1966 — assault with intent to rape, and breaking and entering a dwelling house with intent to commit rape. The defendant at the time was a patient at Boston State Hospital. About 2:25 p.m. on March 29, the defendant said to a male practical nurse at the hospital, who asked where his trousers were, “I want to tell you something. 1 did something wrong. I raped a woman.” Counsel who argued the case on appeal did not represent the defendant at the trial.
1. An expert for the Commonwealth, Dr. Malcolm Ros-enblatt, testified that he had an opinion as to the sanity of the defendant which was, “That according to the M’Nagh-ten rule 1 he was legally sane.” The defendant moved to *546 have the answer struck. The judge ruled, “I will strike out the part about the M’Naghten rule. I will allow the last part to stand.” The defendant excepted “to the part of the answer the Court did not strike.”
The rule which has prevailed in this Commonwealth was first expressed by Shaw, C.J., in
Commonwealth
v.
Rogers,
In the light of this rule, the judge’s action in respect of Dr. Rosenblatt’s answer was prejudicially erroneous. The witness did not testify that in his view, McHoul, according to Massachusetts law, was sane. It is beside the point whether he would have. He did not testify in respect of irresistible impulse. The judge’s ruling left before the jury a statement, attributable to a qualified physician, not in fact made by him. It presented to the jury, in terms conclusive of the issue that they alone were to pass on, an unsupported statement.
2. The defendant excepted to the refusal of the judge to charge in the words of § 4.01 of the American Law Institute ’s Model Penal Code, Proposed Official Draft (1962) p. 66: “Section 4.01 Mental Disease or Defect Excluding Responsibility. (1) A person is not responsible for crimi *547 nal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality [wrongfulness] of his conduct or to conform his conduct to the requirements of law. ’ ’
For the reasons stated below (point 2 [b]), we regard the Code definition as an evolutionary restatement of our rule rather than a substantively new rule, which, of course, it is in those jurisdictions that adopt its dual test to replace the single cognitive test of the M’Naghten rule. The requests in the language of § 4.01 were fully adequate to direct attentiоn to the dual test of criminal responsibility as it has been stated in our cases. In the light of those cases an instruction in Model Penal Code terms was not required, and a correct instruction would have been in some such words as are quoted in point 1,
supra,
from the
McCann
case. The instruction given was not, however, in words or substance, our dual test. That no exception was taken to the charge as given does not exclude our appraisal of it as not meeting the implicit requirement of the defendant’s requests at least to state our rule in its accepted wording. Furthermore, the error is related to the error discussed in point 1 for which there must be in any event a reversal. We do not decide whether in other circumstances we would be warranted in reviewing the charge. See
Commonwealth
v.
Conroy,
(a) The judge charged the jury substantially in terms of the M’Naghten rule, saying, “ [E]very man is presumed to be sane . . . until the contrary be proved to your satisfaction. To establish a defense upon the ground of insanity, it must be clearly proved that at the time of the committing of the act the party accused was laboring under such a defect of reason from disease of the mind as not to know the nature and quality of the act he was doing, or if he did . . . [know], that he did not lmow he was doing what was wrong. The knowledgе required by the ‘right and wrong’ test is the capacity to distinguish between right and wrong; not in the abstract, but as to the particular act which constituted *548 the crime charged. If such capacity existed at the time of the forbidden act, the accused is fully responsible though in other respects he may have been insane. If such capacity did not exist at the time, the accused is then not responsible. ’ ’ He then added, ‘ ‘ An irresistible impulse to commit а crime in and of itself is no defense to its commission unless it is accompanied by an inability to distinguish between right and wrong and ... [a lack of] awareness of the nature and quality of the acts committed at the time of their commission.”
This instruction wrongly stated that the absence of awareness of wrongdoing must accompany irresistible impulse. We reject the Commonwealth’s suggestion that the defect in the charge may be overlooked because the evidence did not show conduct that was irresistibly impelled. The “burden of proof is on the Commonwealth to prove the defendant mentally responsible for crime
(Commonwealth
v.
Johnson,
We do not pause to consider the defendant’s contention that the charge also erred in shifting from the Commonwealth the burden of establishing guilt beyond a reasonable doubt. See
Commonwealth
v.
Johnson,
(b) There has been widespread agreement on the need for a restatement in modern terms of the dual definition of criminal irresponsibility. For reasons to be stated we believe the Model Penal Code has met this need and has done so in language which will not make the dual test in this jurisdiction a substantially different rule in practice.
■ In
Commonivealth
v.
Chester,
In
Commonwealth
v.
Hartford,
Advantages of the Code definition are stated in the opinion in
United States
v.
Freeman,
Perhaps the single greatest рoint made for the Code definition is that under it, experts will be unrestricted in stating all that is relevant to the defendant’s mental illness. This advantage, however, already exists under our rule, properly applied. We indicated in
Commonwealth
v.
Harrison,
The Code’s expression of the dual test modifies the classical Rogers case wording in three significant respects: (1) the qualification of “capacity” (“substantial capacity”) ; (2) the use of the word “appreciate” rather than “know”; and (3) the rejection of the words “irresistible impulse ’ ’ in stating lack of capacity to control conduct.
We think our test
as applied
has been in all likelihood, in most cases, a “substantial capacity” test. The rule, significantly, has been the criterion applied in the uncertain case. Its main function has not been to say that the idiot or similarly mindless person shall not be convicted; prosecutоrs do not bring such persons to trial. See G. L. c. 123, §§ 99, 100, 100A. A defendant’s sanity comes to trial in cases where psychiatrists can and do hold and state opposing views. All such cases show that psychiatry is far from an exact science and that whether a defendant is to be called sane or insane cannot depend on any certain measurement.
*552
Chief Judge Murrah, in
Wion
v.
United States,
The Code intends that ‘ ‘ a defendant will not be convicted of crime if mental illness has deprived him of effective power to make the right choices in governing his own behavior.” Schwartz, The Model Penal Code, 49 Am. Bar Assn. J. 447, 449. According to the
Freeman
opinion,
supra,
the Code “will remove from the pale of criminal sanctions precisely those who are in no meaningful sense responsible for their actions” (
We turn to the other changes in the language of the definition. Wе think that the use of “appreciate” rather than “know” expresses what the word “know”- in the classical statement of the rule means in the light of modern knowledge. Many psychiatrists, as indicated in the records in recent cases, appear to have recognized this.
“The draft . . . accepts the criticism of the ‘irresistible impulse’ formulation as- inept in so far as it may be impliedly restricted to sudden, spontaneous acts as distinguished from insane propulsions that are accompanied by brooding or reflection. See e.g., Boyal Commission on Capital Punishment, Beport (1953) par. 314, p. 110.” — Comment (3) to § 4.01 of Model Penal Code, Tent. Draft No. 4 (1955), p. 157. This is an important change in respect of that part of the dual test under which the chief controversy arises in many if not most cases, including the case at bar (fn. 7). See United States v. Currens, 290 F. 2d *553 751, 775 (3d Cir.). The new wording, we believe, will tend to minimize misunderstanding and is plainly advantageous. We think that, for some time, many expert witnesses have testified more nearly in accordance with the new definition. Although the issue has been, as Chief Justice Shaw in substance stated, whether the defendant was irresistibly impelled to the act done, the emphasis, in modern times, has inevitably been on the concept expressed in the word “irresistible.”
We think that the statement of Chief Justice Shaw that if there is an irresistible impulse the deed is “not the act of a voluntary agent, but the involuntary act of the body, without the concurrence of a mind directing it, ’ ’ no longer reflects the general understanding of how human beings act. Although the mind may have a part in planning and executing compulsive acts, that circumstance does not prevent the finding of ‘ ‘ irresistible impulse. ’ ’ This 1844 statement is, of course, not an integral part of the rule and its omission in the Code reformulation does not show essеntial variance.
Our view that the Code restates our rule appears to be that of the Tenth Circuit. In
Wion
v.
United States,
*554
The Code definitiоn does not bar such questions as whether the defendant is legally sane. See
Commonwealth
v.
Chapin,
In both New Jersey
(State
v.
Lucas,
30 N. J. 37, 63-72) and Washington
(State
v.
White,
It is appropriate to observe, however, that, in our view, the Code restatement does not suggest a weakening in respect of deterrence. See the
Wion
case,
supra
(
It follows from what we have said that, although the trial of this case under the Rogers rule would have given no basis for claim of error, nevertheless, in cases hereafter tried, the trial is to be conducted and the charge given under the clearer and more understandable words of § 4.01 of the Model Penal Code.
3. We deem it unnecessary to discuss the other exceptions.
Judgments reversed.
Verdicts set aside.
Notes
“ [T]he role (which prevails in England and in the majority of States in this country) . . . laid down in the celebrated
M'Naghten’s Case
in 1843. 10 Cl. & Fin. 200” and which is embraced in our “considerably broader” rule.
Commonwealth
v.
Chester,
The importance of Chief Justice Shaw’s modification of thé M’Naghten rule to add the test of irresistible impulse is universally recognized. From it stems the second part of the rule stated in the American Law Institute’s Model Penal Code. See text, point 2 below.
The Code definition has been adopted or approved, in whole or in part, in several jurisdictions by judicial decision.
United States
v.
Freeman,
In the
Chester
opinion, this court rejected the so called
Durham
case rule, or “product’’ test
(Durham
v.
United States,
The opinion in the Freeman case notes that nine years of research, exploration, and consideration by the reporters and an advisory committee of judges, lawyers, psychiatrists, and penologists underlay the Code restatement. The Code formulation, the opinion said, "views the mind as a unified entity and recognizes that mental disease or defect may impair its functioning in numerous ways. The rule, moreover, reflects awareness that from the perspective of psychiatry absolutes are ephemeral and gradations are inevitable. By employing the telling word ‘substantial’ . . . the rule emphasizes that ‘any’ incapacity is not sufficient . . . but that ‘total’ incapacity is also unnecessary. Thе choice of the word ‘appreciate’ rather than ‘know’ . . . also is significant; mere intellectual awareness that conduct is wrongful, when divorced from appreciation or understanding of the moral or legal import of behavior, can have little significance. . . . Expert testimony . . . will be admissible whenever relevant but always as expert testimony —■ and not as moral or legal pronouncement. Believed of their burden of divining prеcise causal relationships, the judge or jury can concentrate upon the ultimate decisions which are properly theirs, fully informed as to the facts. ’ ’
There is an especial need in murder cases (and most insanity trials are in such cases) for permitting psychiatrists to state the extent of the impairment of capacity apart from an opinion whether it had reached the point of legal insanity (criminal irresponsibility within the definition). This stems from our statute which allows the jury to recommend against the death penalty. G. L. c. 265, § 2. In State v. Lucas, 30 N. J. 37, 87, Weintraub, C.J., in a concurring opinion said, "I have no doubt that . . . [full psychiatric] testimony belongs in the case for that purpose. I am convinced the Legislature so intended when ... it provided that the jury shall fix the punishment. . . . The mental condition of a man is so inseparable from the issue of a just disposition — just to him and to society — that it is inconceivable that the Legislature intended to exclude it. ’ ’
In this case also, in general, the psychiatrists were permitted to state their views in terms of modern psychiatric concepts. Dr. Eobey, the clinical director of the Bridgewater State Hospital for the Criminally Insane, called by the defendant, had seen MeHoul ten to fifteen or more times. On March 29, 1966, the defendant was mentally ill; he had also a brain disease and mental deficiency “making a fairly serious problem psyehiatrically.” He was mentally ill within the definition of G. L. e. 123, § 1. Dr. Eobey would expect the brain damage he had referred to would cause a defect in the defendant’s judgment or his ability to control his behavior. The defendant was diagnosed to have a schizophrenic reaction, one of the more serious of the mental illnesses. It affects the patient’s ability to test reality, to understand and recognize what is rеal and what is not real. The defendant had shown overt paranoid signs, and depression “to the point of even being suicidal,” and at “one point he showed . . . catatonic signs.” The symptoms would come and go. On cross-examination, Dr. Eobey testified that, when he discharged the defendant as competent to stand trial, he was aware the defendant could be sexually dangerous. The record facts in respect of a prior commitment included two charges of breaking and entering with intent to commit rape. On March 29, 1966, the defendant “knew in the intellectual sense the difference between right and wrong” and was aware of the nature and the quality of his actions. Q. “And even though you may say that his actions were impulsive . . . you cannot consider them as irresistibly so, can you?” A. “Yes, I could, but this is an opinion I cannot— [answer unfinished].” As to irresistibleness of the defendant’s action on March 29, 1966, Dr. Eobey was of “the opinion that he could have been irresistibly impelled.” “I cannot say clearly.” “I am giving an educated opinion.”
In the
Dusky
ease, the court went beyond our view saying,
“
[W]e would hesitate to reverse a ease . . .
if
the charge appropriately embraces and requires positive findings as to 3 necessary elements, namely, the defendant’s
cognition,
his
volition,
and Ms
capacity to control
his behavior. . . . We think this approach to be sound because it preserves and builds upon those elements of M’Naghten and of irresistible impulse wMch are acceptable in these days and yet modernizes them in terms wMch a jury can grasp and apply. ’ ’
Feguer
v.
United States,
302
F.
2d 234, 244-245 (8th Cir.), cert. den.
See Model Penal Code, Proposed Official Draft (1962) § 4.07 (4) “. . . Form of Expert Testimony When Issue [of Besponsibility] is Tried.” That section is, of course, not in any way involved in our approval of § 4.01.
See
United States
v.
Currens,
The usual dilemma is whether in the particular ease the impulse was irresistible. No expert can answer, with scientific or medical certainty, whether it was impulse not resisted or impulse irresistible. That is the basis of thoughtful criticism of the dual test as distinguished from the M’Naghten rule. See 37 Col. L. Rev. 701, 757. This dilemma remains under the “substantial capacity” test. Experts, if asked whether there was “substantial capacity,” may therefore be expected to differ in their answers.
State
v.
Poulson,
