How have the courts interpreted the standard jury instruction in a mental health case?

Defendant contends the instruction is ambiguous and misleading in several ways. However, we find no error. The standard instruction correctly and adequately explained the applicable law to the jury, and the court was not required to rewrite it sua sponte. "The trial court cannot reasonably be expected to attempt to revise or improve accepted and correct jury instructions absent some request from counsel." (People v. Wolcott (1983) 34 Cal.3d 92, 108-109, 192 Cal.Rptr. 748, 665 P.2d 520.)

Defendant first contends that the reference to a "mental disease or mental defect" prevented the jury from considering the effects of both in [1 Cal.4th 536] combination. This is an unreasonable interpretation of the instruction. Although the court did not expressly state the jury could consider both a disease and a defect, it did not prohibit such consideration. No reasonable juror would believe an insanity finding could be based upon a mental defect or upon a mental disease, but not both. If defendant believed the instruction was incomplete or needed elaboration in this regard, it was his responsibility to request an additional or clarifying instruction. (People v. Bell (1989) 49 Cal.3d 502, 550, 262 Cal.Rptr. 1, 778 P.2d 129 [no penalty phase error in referring to "mental disease" without also referring to "mental defect"].)