Penal Code section 1368 governs incompetence to stand trial. A competency hearing, pursuant to section 1368, requires an evaluation of whether a defendant understands the nature of the criminal proceedings and is able to rationally assist in a defense. (See People v. Lawley (2002) 27 Cal.4th 102, 139 request that defendant be examined for signs of being under the influence of controlled substances is not the equivalent of a declaration of doubt as to defendant's competency within the meaning of 1367.) In People v. Davis (1995) 10 Cal.4th 463, the defendant asserted that the trial court had a sua sponte duty to conduct a Penal Code section 1368 hearing based on reports of defense counsel concerning the defendant's anger, fear of mistreatment in jail, lack of cooperation, and insistence on standing in the doorway of the courtroom during the penalty phase of trial. Rejecting this claim, our Supreme Court noted: "Under the applicable substantial evidence test, 'more is required to raise a doubt than mere bizarre actions or bizarre statements or statements of defense counsel that defendant is incapable of cooperating in his defense or psychiatric testimony that defendant is immature, dangerous, psychopathic, or homicidal or such diagnosis with little reference to defendant's ability to assist in his own defense.'" (People v. Davis, supra, at p. 527, quoting People v. Laudermilk (1967) 67 Cal.2d 272, 285.) Section 1368, subdivision (a), which sets forth the procedure for implementing section 1367 protections, provides: "If, during the pendency of an action and prior to judgment, a doubt arises in the mind of the judge as to the mental competence of the defendant, he or she shall state that doubt in the record and inquire of the attorney for the defendant whether, in the opinion of the attorney, the defendant is mentally competent." If, in response, defense counsel informs the court of a belief that the defendant is or may be incompetent, the court shall order the question of the defendant's mental competence determined at a formal hearing held pursuant to sections 1368.1 and 1369. ( 1368, subd. (b).) The court may order a competency hearing even if counsel believes the defendant is competent. ( 1368, subd. (b).) But, "a doubt in the mind of counsel, or anyone else other than the trial court is not sufficient to require a hearing" under section 1368. (People v. Wade (1959) 53 Cal.2d 322, 336, disapproved on other grounds in People v. Carpenter (1997) 15 Cal.4th 312, 381-382.) When a trial court has ordered a hearing to determine a defendant's competence, it must suspend all proceedings in the criminal prosecution until that determination has been made. ( 1368, subd. (c).) Failure to do so renders any subsequent judgment a nullity, as an act in excess of jurisdiction. (People v. Superior Court (Marks), supra, 1 Cal.4th at pp. 70-71.) "'A trial court is required to conduct a competence hearing, sua sponte if necessary, whenever there is substantial evidence of mental incompetence. Substantial evidence for these purposes is evidence that raises a reasonable doubt on the issue. '" (People v. Rodrigues (1994) 8 Cal.4th 1060, 1110, quoting People v. Howard (1992) 1 Cal.4th 1132, 1163.) "This doubt which triggers the obligation of the trial judge to order a hearing on present sanity is not a subjective one but rather a doubt to be determined objectively from the record." (People v. Sundberg (1981) 124 Cal.App.3d 944, 955-956; see People v. Tomas (1977) 74 Cal.App.3d 75, 90.) On appeal, a "trial court's decision whether or not to hold a competence hearing is entitled to deference, because the court has the opportunity to observe the defendant during trial." (People v. Rogers, supra, 39 Cal.4th at p. 847.) Furthermore, "trial counsel's failure to seek a competency hearing ... is significant because trial counsel interacts with the defendant on a daily basis and is in the best position to evaluate whether the defendant is able to participate meaningfully in the proceedings." (Id. at p. 848.) But the failure to declare a doubt and conduct a hearing when there is substantial evidence of incompetence also requires reversal of the judgment of conviction. (Id. at p. 847.)