Is a defendant's failure to instruct sua sponte that malice aforethought is a reversible error?

Defendant claims the court erred in failing to instruct sua sponte that malice aforethought requires "an awareness [by the defendant] of a [45 Cal.3d 66] duty imposed by law not to commit [the act] followed by the commission of the forbidden act despite that awareness." We rejected a similar argument in People v. Cruz (1980) 26 Cal.3d 233, 252-253, 162 Cal.Rptr. 1, 605 P.2d 830, holding that the failure to give such an instruction constitutes reversible error only if there is "evidence deserving of consideration that defendant lacked an awareness of that duty. [Citations.]" We further stated, "[w]ithout relevant evidence, it is not reasonably probable that a result more favorable to defendant would have been reached had the instruction been given; and error, if any, was not prejudicial. [Citations.]" (Id., at p. 253, 162 Cal.Rptr. 1, 605 P.2d 830.) Here, the only possible evidence bearing on the issue was evidence of defendant's ingestion of drugs prior to the murders, yet there was no evidence whatever that the drugs affected defendant's awareness of his duty not to kill. The jury rejected defendant's claim of diminished capacity, and there is no other evidence in the record indicating that defendant lacked an awareness of the duty not to kill. Indeed, the record shows that defendant expressly declined "to kill any babies," evidencing an awareness of that duty.