Appellant, after waiving jury trial, was convicted of a federal narcotics violation. His defenses were entrapment and insanity. After hearing extensive evidence on both defenses, the trial court resolved the factual issues against appellant and sentenced him to five years’ imprisonment, “strongly” recommending his assignment to the federal narcotics center at Lexington, Kentucky.1 Appellant’s principal contention on appeal is that entrapment was shown as a matter of law. We find no merit in this argument.
This case, however, presents yet another facet of the recurring problem of a defendant’s competence to stand trial. Several months before trial, appellant, who had a life history of narcotic use and addiction, was committed to Saint Elizabeths Hospital for a 60-day mental examination. He suffered withdrawal symptoms when his narcotics supply was cut off at the beginning of his commitment. He was then diagnosed as “without mental disorder and drug addiction in remission.” The Hospital, without referring to appellant’s narcotic problem, reported that he was competent to stand trial, and the District Court so determined without conducting a hearing. Appellant was released on bail following his mental examination and soon resumed his use of narcotics. At trial he took the stand in his own defense and admitted that he had been using narcotics throughout the trial, even during the lunch recess that very day. The judge thereupon revoked appellant’s bond and had the jail notified that he “may be subject, possibly, to withdrawal symptoms.” The trial was *922concluded the next day without inquiry whether appellant was undergoing a withdrawal reaction. At no time either before or during trial did appellant request a hearing on his competence to stand trial.
Current medical knowledge indicates that use of narcotics often produces a psychological and physiological reaction known as an acute brain syndrome, which is a “basic mental condition characteristic of diffuse impairment of brain tissue function.” The characteristic symptoms of the syndrome are impairment of orientation; impairment of memory; impairment of all intellectual functions including comprehension, calculation, knowledge and learning; impairment of judgment; and lability and shallowness of affect.2 A court-appointed psychiatrist testified at trial that he had examined appellant on several occasions subsequent to his mental examination at Saint Elizabeths and found him under the influence of narcotics. During these interviews appellant gave “fairly classical evasive answers * * *. When you start to press the patient a little, he began to get somewhat disturbed and he began to show very, very poor judgment.” He “began to become much more disorganized * * * and he began to show memory defects, and these memory defects were picked up in an insidious manner.” The doctor concluded that appellant’s use of narcotics had produced an acute brain syndrome, a mental disorder whose characteristic symptoms appellant exhibited. “[A]lthough there was a general degree of orientation * * * where you have to use some type of memory recall in addition to some degree of orientation, the patient was grossly impaired.” This testimony was corroborated in many respects by the Government’s expert witness who, although he had never examined appellant when under the influence of narcotics, stated generally that use of narcotics could and often did produce an acute brain syndrome and recited the classical symptoms of that disorder.3
That a narcotics-induced acute brain syndrome may affect a defendant’s competence to stand trial is readily apparent. According to the Supreme Court, the test of competency
must be whether [the accused] * * has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding— and whether he has a rational as well as factual understanding of the proceedings against him.4
Subsumed under this formulation is the requirement that the defendant’s memory and intellectual abilities, which are crucial to the construction and presentation of his defense, must not be substantially impaired by mental disorder.5 Yet it is these very mental faculties *923which the acute brain syndrome caused by narcotics most affects.6
Subsequent to the trial in this case, the Supreme Court considered a somewhat similar problem in Pate v. Robinson, 383 U.S. 375, 86 S.Ct. 836, 15 L.Ed.2d 815 (1966). There a state-court criminal defendant never requested a competency hearing. At trial, however, the defendant presented an insanity defense, and produced several lay witnesses who testified to his various bizarre acts and irrational behavior. The Supreme Court first declared that trial and conviction of an incompetent defendant constituted a denial of a fair trial. The Court then ruled that evidence raising a substantial doubt regarding the defendant’s competency imposed a constitutional duty on the trial court to conduct, on its own motion if the defendant failed to request it, an inquiry into the defendant’s competence to stand trial.7
We. believe the record in this case demonstrates, as did that in Pate v. Robinson, a sufficient likelihood of incompetence to have imposed on the trial court a duty to inquire into appellant’s competency. This is not, of course, to say that a defendant under the influence of narcotics is necessarily incompetent. Narcotic use does not invariably produce an acute brain syndrome, nor is every syndrome of the same degree of severity. The effects of narcotic use will vary depending on the amount of drugs taken, the degree of tolerance developed by the individual, and the idiosyncratic reaction of the person to the drugs. For this very reason, only by a hearing can it be determined whether any particular defendant is incompetent because of his use of drugs.8
We also believe that a competency hearing is constitutionally required if it appears that a defendant may be suffering from withdrawal symptoms during trial. Withdrawal is a recognized medical illness. Its effects typically include various physical reactions such as perspiration, waves of gooseflesh, muscle twitch, body aches, hot and *924cold flashes, restlessness, sleeplessness, nausea, vomiting, and diarrhea. The subject is in extreme physical misery. He may try to withdraw within himself, or may exhibit highly individualized patterns of anxious and irrational behavior, such as becoming quite antagonistic, threatening suicide, assuming bizarre postures, or exaggerating his distress in dramatic ways, often as a purposive attempt to obtain drugs.9 These physical and psychological symptoms of withdrawal could very well render a defendant incompetent to stand trial. He may be physically incapacitated from following the evidence or from discussing it with counsel, or he may be so preoccupied with his real or imagined suffering as to lose all interest in his case and desire only that it end as quickly as possible. Inquiry and a determination that the defendant is in fact competent therefore seems a prerequisite to the conduct or continuation of a fair trial.
The trial judge in this case, having observed appellant, may have thought him competent. But it plainly appears from Pate v. Robinson that' appellant’s apparent alertness and understanding during trial cannot wipe out the uncontradicted testimony that his memory and other intellectual functions became severely impaired when he was under the influence of narcotics. While his demeanor at trial may be a relevant factor, it is by no means the only one and it cannot obviate the need for a hearing on his competence.10 This reasoning applies with particular force to a defendant who may be under the influence of narcotics, since the symptoms and effects of an acute brain syndrome produced by narcotics will often not be apparent to a lay observer, even a judge, but only to an expert. Even then a careful examination would seem necessary to determine the extent to which the defendant’s memory and other rational faculties have been impaired by the drugs.11
Nor can the District Court’s previous determinatioi of competency relieve the trial court of its constitutional duty to conduct an inquiry at the time of the trial. In Pouncey v. United States,12 the defendant had been found *925competent by the District Court following examination at Saint Elizabeths Hospital, but his behavior at trial cast doubt on that finding. We there stated that
[A] judge’s responsibility to guard against the possibility that an accused person may have become incompetent does not end when the trial begins. A hospital report is only a prediction that when the accused is tried he will be able to participate adequately in the proceedings. Later developments may throw doubt on the prediction, particularly when, as in this case, the report does not show the hospital’s understanding of “competence”, the tests it employed, or the certainty of its diagnosis.13
We therefore held that, despite the earlier finding of competency, the trial court had erred by failing to inquire further at the time of the trial.
In the present case, the predictive value of the Hospital report and of the initial judicial determination of appellant’s competency was vitiated by appellant’s resumption of his use of narcotics following his examination. This fact, brought out at trial, should have put the trial court on notice that appellant might then have become incompetent. Furthermore, although the trial court recognized the possibility that appellant might suffer withdrawal symptoms upon incarceration during the trial, it allowed the trial to proceed without the slightest recognition that any competency problem might then arise. The decisions in Robinson14 and Pouncey teach that the trial court’s failure to conduct, sua sponte, an inquiry into his competence denied appellant a “fair trial.” 15
The only appropriate remedy for this constitutional violation is a new *926trial.16 A retrospective determination of competency is difficult at best. It is virtually impossible where, as here, there is no contemporaneous testimony or evidence of appellant’s competence at the time of trial and where his present condition — incarcerated and presumably no longer under the influence of narcotics or suffering from withdrawal — is unquestionably different. An expert who now examined him could do no more than speculate unduly about his mental condition at his trial a year ago.17
Reversed.
. The trial court showed a particularly sensitive concern regarding the effects of appellant’s narcotic addiction on his insanity defense and on the issue of sentencing and place of detention.
. American Psychiatric Ass’n, Diagnostic and Statistical Manual : Mental Disorders 14-15 (1952). See Noyes & Kolb, Modern Clinical Psychology 86-87, 142-45 (6th ed. 1963); President’s Advisory Committee on Narcotic and Drug Abuse, Final Report 1 (1963).
. Both witnesses analogized a narcotic-induced acute brain syndrome to the symptoms of intoxication caused by alcohol. See, e. g., Maurer & Vogel, Narcotics and Narcotic Addiction 82 (2d ed. 1962) [hereinafter cited as Maurer & Vogel].
. Dusky v. United States, 362 U.S. 402, 80 S.Ct. 788, 4 L.Ed.2d 824 (1960) (emphasis added). This test, in our opinion, is equivalent to the standard set forth in D.C.Code § 24-301 (a) (1961): “ * * * that the accused is of unsound mind or is mentally incompetent so as to be unable to understand the proceedings against him or properly to assist in his own defense. * # lit >»
. See, e. g., United States v. Sermon, 228 F.Supp. 972 (W.D.Mo.1964); Judicial Conference of the District of Columbia Circuit, Report of the Committee on Problems Connected With Mental Examination of the Accused in Criminal Cases, Before Trial 121-22, 124, 131-32 (1965).
. See, e. g., authorities cited in note 2 supra. Cf., e. g., President’s Ad Hoc Panel On Drug Abuse, Progress Report 16-21 (1962); Joint Committee oe the American Bar Ass’n & the American Medical Ass’n On Narcotic Drugs, Interim and Final Reports 36-42 (1961).
Another very common symptom of heroin or morphine use is that the user experiences a feeling of euphoria and a concomitant reduction in anxiety and tension. See, e. g., President’s Ad Hoc Panel On Drug Use, Progress Report 20 (1962); Maurer & Vogel 60-61, 73-74. The drugs therefore might lower the * * * tensions that are actually
healthy and perhaps essential for proper participation in an adversary court proceeding. A euphoric feeling may impair the ability of the accused meaningfully to assist his counsel.
Judicial Coneerence oe the District oe Columbia Circuit, Report oe the Committee On Problems Connected With Mental Examination oe the Accused. In Criminal Cases, Before Trial 122 (1965).
. All nine justices agreed to these constitutional propositions. The dissent of Justices Harlan and Black was based on their view that the evidence at trial was insufficient to raise a substantial doubt as to the defendant’s competence. See 383 U.S. at 387-391, 86 S.Ct. 836, 15 L.Ed.2d 815.
Pate v. Robinson is but one of the most recent cases reflecting the Supreme Court’s increasing concern during the last decade with the constitutional dimensions of the problem of competence to stand trial. See, e. g., Bishop v. United States, 96 U.S.App.D.C. 117, 223 F.2d 582 (1955), rev’d per curiam, 350 U.S. 961, 76 S.Ct. 440, 100 L.Ed. 835 (1956) ; Dusky v. United States, supra note 4; Sanders v. United States, 373 U.S. 1, 83 S.Ct. 1068, 10 L.Ed.2d 148 (1963). Cf. Rees v. Peyton, 384 U.S. 312, 86 S.Ct. 1505, 16 L.Ed.2d 583 (1966).
. The hearing, of course, need not be a lengthy and involved proceeding. However, as a minimum we think the inquiry must be of record and both parties must be given the opportunity to examine all witnesses who testify or report on the accused’s competence. The trial court would not be free to base its decision on material not in the record or on private conversations with doctors who had examined the defendant.
. See, e. g., President’s Ad Hoc Panel on Drug Abuse, Progress Report 21 (1962); Joint Committee oe the American Bar Ass’n & the American Medical Ass’n on Narcotic Drugs, Interim and Final Reports 42-44 (1961); Maurer & Vogel 85-86, 184; Bowman, Narcotic Addiction and Criminal Responsibility under Durham, 53 Geo.L.J. 1017, 1039 (1965).
As with the symptoms of an acute brain syndrome produced by narcotics, the degree of severity of withdrawal symptoms and their particular manifestations vary greatly depending on the individual and on the duration and intensity of his use of the drugs. See, e. g., Maurer & Vogel 85-86.
. See 383 U.S. at 385-386, 86 S.Ct. 836.
. See, e. g., Maurer & Vogel 84; Noyes & Kolb, Modern Clinical Psychiatry 144 (6th ed. 1963). The court-appointed psychiatrist in this case testified that a
* * * good number of narcotic addicts do not become euphoric, they become really, in a manner of speaking, for superficial purposes, almost quite normal and they act quite normal superficially.
* # * * *
* » * for example when he [appellant] came into the office he appeared quite normal and then when we really began to test his limits it became fairly apparent that he was under the use of narcotics.
The Supreme Court has also recognized this difficulty. In Sanders v. United States, 373 U.S. 1, 83 S.Ct. 1068, 10 L.Ed.2d 148 (1963), the Court ruled that a hearing was necessary under 28 U.S.C. § 2255 in order to test a claim of incompetence based on narcotic use during trial, and stated that “Whether or not [the defendant] * * * was under the influence of narcotics [during trial] would not necessarily have been apparent to the trial judge.” Id. at 20, 83 S.Ct. at 1079. Further, because lay observations will often be inaccurate, the fact that defense counsel did not think defendant incompetent, although of evidentiary value, can never be dispositive.
. 121 U.S.App.D.C. 264, 349 F.2d 699 (1965). Cf. Stone v. United States, 358 F.2d 503 (9th Cir. 1966).
. Id., at 265, 349 F.2d at 700 (footnote omitted). The report of Saint Elizabeths Hospital in this case did not contain a diagnosis but merely stated that “As a result of our examination and observation, it is our opinion that [appellant] is mentally competent for trial.” We have complained long and often, without success, that such conclusionary and uninformative boilerplate reports cannot assist the court in making any legal determination. See, e. g., Whalem v. United States, 120 U.S.App.D.C. 331, 339-341, 346 F.2d 812, 820-22 (1965) (dissenting opinion); Holloway v. United States, 119 U.S.App.D.C. 396, 398-399, 343 F.2d 265, 267-268 (1964). Recent cases indicate new dangers concerning these reports. For example, in May v. Cameron, H.C. No. 572-65 (D.D.C. Feb. 16, 1965), petitioner, a patient at Saint Elizabeths, alleged only that the Hospital had interfered with his right of free access to the courts and sought an order to prevent this interference. The Hospital Superintendant made this totally irrelevant reply to an order to show cause: “the medical staff * * * are of the opinion that [petitioner] has not recovered from his abnormal mental condition * * * and, the respondent is unable to certify that petitioner will not be dangerous to himself or others * * For a similar instance of a completely conclusionary and irrelevant response see Leach v. United States, 122 U.S.App.D.C. 280, 282, 353 F.2d 451, 452-453 (1965). The question arises whether the Hospital’s program of testing and examination is directed to the court’s inquiry. But uninformative boilerplate replies hide inadequacies in the methods and reasoning underlying the reports.
. In Whalem v. United States, 120 U.S.App.D.C. 331, 333-36, 346 F.2d 812, 814-17, cert. denied, 382 U.S. 862, 86 S.Ct. 124, 15 L.Ed.2d 100 (1965), we held that in the absence of objection to a conelusionary hospital report the District Court has discretion to make a finding of competence solely on the basis of the report. But in the present case, appellant’s behavior following such report patently undercut its predictive value. See Pouncey v. United States, supra note 12, 349 F.2d at 700-701. We therefore need not decide whether Pate v. Robinson has, in effect, overruled that portion of our Whalem decision.
. The requisite hearing need not have caused a major disruption to the trial. Appellant’s admission of narcotic use occurred at the end of an afternoon session and the trial court could have ordered a mental examination of appellant by the Legal Psychiatric Services that night with a report to be filed the next morning.
. See, e. g., Pate v. Robinson, 383 U.S. 375, 386-387, 86 S.Ct. 836, 15 L.Ed.2d 815 (1966) ; Dusky v. United States, 362 U.S. 402, 80 S.Ct. 788, 4 L.Ed.2d 824 (1960) ; Holloway v. United States, 119 U.S.App.D.C. 396, 343 F.2d 265 (1964). Rees v. Peyton, supra note 7, is not to the contrary since the issue there was petitioner’s competence to withdraw his writ of certiorari not his competence to stand trial. Similarly, Bishop v. United States, supra note 7, and Sanders v. United States, supra note 7, as well as all other cases arising on collateral attack, are inapposite because the only possible way to determine the question of competence to stand trial in this situation is by retrospective hearing. On the other hand, the Supreme Court has forcefully indicated that where the question of competence is presented on direct appeal and a retrospective hearing is not inevitable, the proper procedure is to vacate the conviction and order a prospective competency hearing followed by a new trial if the accused is found competent. Dusky v. United States, supra; Pate v. Robinson, supra. Statements and holdings to the contrary found in cases decided by this court prior to Bushy must, of course, be disregarded to the extent that they conflict with these Supreme Court decisions.
. The fact that appellant was examined by a court-appointed psychiatrist while under the influence of narcotics does not justify a nunc pro tunc hearing since that expert would have to testify from his year-old memory of appellant and since it would be impossible to test his opinion by having appellant examined by another psychiatrist.