(a)Evidence of mental disease, mental defect, or mental disorder shall not be admitted to show or negate the capacity to form any mental state, including, but not limited to, purpose, intent, knowledge, premeditation, deliberation, or malice aforethought, with which the accused committed the act. Evidence of mental disease, mental defect, or mental disorder is admissible solely on the issue of whether or not the accused actually formed a required specific intent, premeditated, deliberated, or harbored malice aforethought, when a specific intent crime is charged.
(b)As a matter of public policy there shall be no defense of diminished capacity, diminished responsibility, or irresistible impulse in a criminal action or juvenile adjudication hearing.
(c)This section shall not be applicable to an insanity hearing pursuant to Section 1026.
(d)Nothing in this section shall limit a court’s discretion, pursuant to the Evidence Code, to exclude psychiatric or psychological evidence on whether the accused had a mental disease, mental defect, or mental disorder at the time of the alleged offense.
Notes of Decisions
Cited in
59
cases (
12 in the last 5 years), 1982–2026 · leading case:
People v. Christian S., 872 P.2d 574 (Cal. 1994).
People v. Christian S., 872 P.2d 574 (Cal. 1994).
· cites it 4× “For example, Penal Code section 28, subdivision (b) states, "As a matter of public policy there shall be no defense of diminished capacity, diminished responsibility, or irresistible impulse in a criminal action or juvenile adjudication hearing.”
People v. Vieira, 106 P.3d 990 (Cal. 2005).
· cites it 2× “The court, however, barred Cerny from testifying before the jury at the guilt phase, explaining: "Penal Code Section 28 requires that such evidence regard a .”
In re Cordero, 756 P.2d 1370 (Cal. 1988).
· cites it 4× “(Pen. Code, § 28.) It was refused on that ground.”
State v. Provost, 490 N.W.2d 93 (Minn. 1992).
· cites it 4× “Twenty-four of these states, in one fashion or another, have allowed such testimony ( see footnote 3, infra ), while 18 states have taken a contrary view. Cases which admit psychiatric evidence include People v.”
People v. Nieves, 485 P.3d 457 (Cal. 2021).
“Mental state testimony Penal Code sections 28 and 29 “permit introduction of evidence of mental illness when relevant to whether a defendant actually formed a mental state that is an element of a charged offense, but do not permit an expert to offer an opinion on whether a…”
Johnson v. State, 439 A.2d 542 (Md. 1982).
· cites it 2× “); Idaho Code § 18-208 (1) (1979, 1981 Supp.); Mo. Ann. Stat. § 552.030 (3) (1) (Vernon) (1981 Supp.”
People v. Jackson, 152 Cal. App. 3d 961 (Cal. Ct. App. 1984).
· cites it 4× “) II Penal Code Sections 28 and 29 Do Not Impose an Unconstitutional Limit on the Due Process Right to Present a Defense The theory of Jackson’s defense at trial was that he did not have the mental state necessary to constitute attempted murder in the first degree.”
Hernandez v. Martel, 824 F. Supp. 2d 1025 (C.D. Cal. 2011).
· cites it 5× “See CaLPenal Code § 28. While the change in the law did not affect petitioner’s trial because he committed the crimes before the referendum passed, the existence of the initiative may lend some context to petitioner’s trial.”
State v. Wilcox, 436 N.E.2d 523 (Ohio 1982).
· cites it 2× “Cal. Penal Code Section 28 (1982 Supp.); West’s Cal.”
State v. Ellis, 963 P.2d 843 (Wash. 1998).
· cites it 2× “In the meantime, however, California, which had pioneered the concept of diminished capacity, abolished the diminished capacity defense by statute in 1981, Cal. Penal Code § 28 , and statutorily prohibits testimony by an expert as to a defendant’s mental state required for the…”
Crittenden v. Ayers, 624 F.3d 943 (9th Cir. 2010).
“2d 588, 593 (1991) (quoting Cal.Penal Code § 28(a)) (emphasis added by Saille).”
People v. Larsen, 205 Cal. App. 4th 810 (Cal. Ct. App. 2012).
“32, the court pointed out the expert did not opine the defendant was suffering from a mental disease, defect, or disorder when he stabbed the victim. Certainly, as the majority notes, an expert cannot testify on the ultimate issue of whether a defendant had the requisite intent…”
Cal. Penal Code § 28(a): 5 cases
Crittenden v. Ayers, 624 F.3d 943 (9th Cir. 2010).
“2d 588, 593 (1991) (quoting Cal.Penal Code § 28(a)) (emphasis added by Saille).”
Cal. Penal Code § 28(b): 3 cases
State v. Provost, 490 N.W.2d 93 (Minn. 1992).
“Twenty-four of these states, in one fashion or another, have allowed such testimony ( see footnote 3, infra ), while 18 states have taken a contrary view. Cases which admit psychiatric evidence include People v.”
Cal. Penal Code § 28(d): 1 case
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