SPOTTSWOOD W. ROBINSON III, Circuit Judge.
Appellant, a drug addict with schizoid traits, was indicted in seven counts for offenses allegedly committed during the holdup of a store. At his trial, the sole defense was insanity. This issue was submitted to the jury, and it found him guilty on five counts.1 He now contends that the trial judge erroneously refused to enter a judgment of acquittal, and misinstructed the jury on the relationship between his mentality, his addiction and the acts comprising the offenses. We affirm.
I
It is against a background of fundamentals judicially formulated that we must examine appellant’s claim that the evidence required his acquittal. With us, “an accused is not criminally responsible if his unlawful act was the product of mental disease or mental defect,” 2 a standard thus combining a quality of mind and its linkage with the offending conduct. Exculpation entails an “abnormal condition of the mind which substantially affects mental or emotional processes and substantially impairs behavior controls,” 3 and which “made the effective or decisive difference between doing and not doing the act.” 4 An insanity defense, legitimately invoked, though involving narcotism as an operative factor, stands or falls according to the Government’s capability to dispel all reasonable doubt in that regard.5
*989Our decisions also define boundaries within which the interplay of drug addiction is confined. The fact of addiction standing alone, does not permit a finding of mental disease or defect.6 Evidence of that fact, however, has probative value in conjunction with evidence of mental illness,7 and the effect of a deprivation of narcotics on behavioral controls is a relevant circumstance. 8 We have recognized, too, that extensive and protracted addiction may so deteriorate such controls as to produce irresponsibility within our insanity test.9 But we have also made it plain that although a narcotic habit is causally connected with the crime, the defense is negated if the power of self-restraint is not diminished significantly.10
During the nearly five days of trial, three psychiatrists, two psychologists and four laymen gave testimony supplying antithetical answers to most of the critical inquiries. To indicate the decisional possibilities open to the jury, we need only summarize briefly the ultimate facts authorized, more frequently alternatively, by the proofs.11 All experts agreed that appellant was chronically addicted to the use of heroin and that the criminal acts were in some wise connected with his addiction. They also concurred in the opinion that he had schizoid tendencies12 but that, addiction aside, they did not amount to mental illness.13 One psychiatrist felt that appellant had a schizoid personality which led to the addiction, and to mental disease as the combinational result. The other two psychiatrists were firm in their views that appellant was not mentally sick.14
*990In similar fashion, the evidence suggested divergent solutions for the problems of causality. The one psychiatrist finding mental illness opined that the offenses charged were its product,15 but much of the testimony indicated the contrary. Two police officers stated, on personal observation, that appellant did not appear to be in a stage of withdrawal when arrested. The evidence discloses no symptom of withdrawal until about twenty hours after he was taken into custody. The two remaining psychiatrists concluded that withdrawal when the offenses were committed was medically improbable.16
In this milieu, the trial judge was called upon to “determine whether upon the evidence, giving full play to the right of the jury to determine credibility, weigh the evidence, and draw justifiable inferences of fact, a reasonable mind might fairly conclude guilt beyond a reasonable doubt.”17 Of course, as only recently we said, “the facts adduced as to the existence and impact of an accused’s mental condition may be so overwhelming as to require a judge to conclude that no reasonable juror could entertain a reasonable doubt.”18 But when insanity is raised as a defense to crime, a judgment of acquittal by reason thereof, we have emphasized, should be granted only in exceptional cases.19 And “in view of the complicated nature of the decision to be *991made — intertwining moral, legal, and medical judgments — it will require an unusually strong showing to induce us to reverse a conviction because the judge left the critical issue of criminal responsibility with the jury.” 20 We think it clear that in this case the trial judge left it where it belonged.21
II
After both sides rested, appellant submitted to the court three written requests for instructions to the jury, two of which were granted in substance The other, set forth below,22 was properly denied. The request was inaccurate in its statement that “[a] 11 the psychiatrists who testified * * * stated that in their opinion * * * [the] crimes were causally related to the addiction in the sense that he was deprived of narcotics at the time and was under a compulsive need to obtain them and to obtain money with which to obtain them.”23 Nor was it true that “the relationship of [appellant’s] addiction to the crimes [is] not substantially disputed.” 24 And, to the extent that the request sought to license the jury to “find that his narcotic addiction alone was such a mental abnormality as to substantially affect his mental or emotional processes and substantially impair his behavior controls,” it flew into the face of our previous decisions.25 The trial judge was not required to give the instruction in the shape in which it was proffered 26
Appellant’s present position involves, however, a shift in emphasis as to the interconnection of his addiction and the insanity defense he advanced. While in the trial court the thrust of his claim was that narcotic addiction may of itself be a mental abnormality crippling emotional processes, he now insists that the jury should have been instructed to consider his addiction, not alone but in rela*992tion to other circumstances, as supporting the insanity defense. We have indeed recognized that “[t]here may well be some cases where prolonged and extensive use of narcotics has substantially impaired the capacity to control behavior, and a ‘mental disease’ within our [insanity] standards may result.”27 And when we pointed out that “a mere showing of narcotics addiction, without more, does not constitute ‘some evidence’ of mental disease or ‘insanity’,”28 we hastened to add that this was “not to say that evidence that an accused is an addict is without probative value along with other evidence on the issue of responsibility.” 29 Certainly, considering the evidence, the trial judge might properly have given an instruction focusing consideration on the combination of appellant’s long-standing addiction and other indicia of mental involvement.
But appellant did not request specifically an instruction of the latter type, nor was the charge objected to on account of the fact that the trial judge did not volunteer one. In such circumstances, we would not set any sort of novel precedent were we to ignore the point.30 On the other hand, the evidence was strong, not only as to appellant’s addiction, but also as to a quantum of mental weakness arising independently of it, and appellant’s request did implore, albeit faintly some advice associating the two for the benefit of the jury. We are thus constrained to explore the kind and degree of guidance the trial court afforded in this regard.
The trial judge gave a full and completely fair insanity charge during the course of which twice, for purposes of emphasis, he supplied the basic definition of mental illness:
“A mental disease, or a mental defect, in the eyes of the law for the purpose of this case, includes any abnormal condition of the mind which substantially affect [ste] the mental or emotional processes, and substantially impairs behavioral control.
“The term, ‘behavioral control,’ refers to the processes and ability of a human being to regulate and control his conduct and his actions.”
We note initially that this definition, which the judge described as “the gist of the whole case,” did not exclude, but was itself broad enough to embrace, combina-tional consideration of addiction with other factors in the determination of mental abnormality. Indeed, at one stage of the charge, “addiction” was put on the same plane with “disease” and “defect,” eo nomine, as mental “conditions” which, weighed circumstantially with labels removed, might establish blameworthiness. Referring to the labels, including “narcotic addiction,” the witnesses had used in their testimony, the judge admonished that
“ * * * you must realize that the core of this problem is not one of labels, or technical, medical jargon. It is not a question of whether some condition is classified as being underlying, classified as being a disease, a defect, or addiction.
*993“Bather, the key question that will unlock the door is whether this defendant, at the time he committed the act alleged in the indictment, was suffering from an abnormal condition of the mind and, if so, whether that condition substantially affected his mental or emotional processes and substantially impaired his behavioral control.” (Emphasis supplied.)
Additionally, the trial judge in his charge referred to the “voluminous testimony in this case concerning the narcotic addiction of the defendant,” and told the jury that “[njarcotic addiction, without something more” would not establish insanity. This rather clearly implied that coupled with “something more” addiction might amount to insanity. This implication was soon made explicit when the judge, very much in line with the theory of the defense, informed the jury that it might
“ * * * consider whether the defendant in this case was using drugs at the time of the alleged offense and, if so, whether at the time of the alleged offense, the intake and the effect of the drug so substantially affected his controlled [sic] processes and so substantially impaired his behavioral control so that he could not control his common sense at the time.”
Benefited by hindsight, one may say that the instructions did not connect mentality with addiction as clearly as might have been done. But in our view they did not disfavor but actually encouraged the alliance. It seems to us that there was enough to have the jury understand that any factor or group of factors — including narcotic addiction and barring only “[njarcotic addiction, without something more”— which met the test for insanity would suffice to immunize appellant from conviction.31 We think, too, that an assumption that to have said more might have resulted in a different verdict would involve a high degree of speculation. At the very least, we must appraise the situation as clearly unexceptional and the probability of prejudice as quite doubtful. In these circumstances, we feel that reversal is neither required nor warranted.32
While, on this appeal, we so conclude, we utilize this opportunity to say a word of caution. We trust that, with what we have said, it is now clear that defense counsel should ask for an instruction on the combinational effect of any narcotic addiction and mental deficiency indicated by substantial evidence. Trial judges will in the future be well advised to consider such an instruction in appropriate situations, whether requested or not.33 We affirm here because we perceive no prejudice, but in another case there quite easily could be. A proper determination *994of criminal responsibility is too transcendent a matter to be exposed to that sort of risk.
Affirmed.