CALCRIM No. 3428. Mental Impairment: Defense to Specific Intent or Mental State (Pen. Code, § 28)
Judicial Council of California Criminal Jury Instructions (2024 edition)
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3428.Mental Impairment: Defense to Specific Intent or Mental
State (Pen. Code, § 28)
You have heard evidence that the defendant may have suffered from a
mental (disease[,]/ [or] defect[,]/ [or] disorder). You may consider this
evidence only for the limited purpose of deciding whether, at the time of
the charged crime, the defendant acted [or failed to act] with the intent
or mental state required for that crime.
The People have the burden of proving beyond a reasonable doubt that
the defendant acted [or failed to act] with the required intent or mental
state, specifically: <insert specific intent or mental state
required, e.g., “malice aforethought,” “the intent to permanently deprive the
owner of his or her property,” or “knowledge that . . .”>. If the People
have not met this burden, you must find the defendant not guilty of
<insert name of alleged offense>.
<Repeat this paragraph for each offense requiring specific intent or a
specific mental state.>
[Do not consider evidence of mental (disease[,]/ [or] defect[,]/ [or]
disorder) when deciding if <insert name of nontarget
offense> was a natural and probable consequence of <insert
name of target offense>.]
New January 2006; Revised March 2017
BENCH NOTES
Instructional Duty
The court has no sua sponte duty to instruct on mental impairment as a defense to
specific intent or mental state; however, the trial court must give this instruction on
request. (People v. Saille (1991) 54 Cal.3d 1103, 1119 [2 Cal.Rptr.2d 364, 820 P.2d
588].) The jury may consider evidence of mental impairment and its effect on the
defendant’s ability to form any mental state required for the offense charged. (Pen.
Code, § 28; People v. Reyes (1997) 52 Cal.App.4th 975, 983-985 [61 Cal.Rptr.2d
39] [relevant to knowledge element in receiving stolen property]; People v. Mendoza
(1998) 18 Cal.4th 1114, 1131-1134 [77 Cal.Rptr.2d 428, 959 P.2d 735] [voluntary
intoxication relevant to mental state in aiding and abetting].)
Evidence of mental impairment may not be considered for general-intent crimes,
unless there is an element, such as knowledge, that requires a specific mental state.
(People v. Reyes, supra, 52 Cal.App.4th at pp. 983-985; People v. Mendoza, supra,
18 Cal.4th at pp. 1131-1134 [aiding and abetting].)
In all cases, the court must insert the specific intent or mental state required and the
offense for which the mental state is an element. (See People v. Hill (1967) 67
1018
Cal.2d 105, 118 [60 Cal.Rptr. 234, 429 P.2d 586].)
Give the bracketed paragraph that begins with “You must not consider evidence of
mental” when instructing on aiding and abetting liability for a nontarget offense.
(People v. Mendoza, supra, 18 Cal.4th at p. 1134.)
In an attempted murder case, it was error to insert “intent to kill” instead of
“express malice” as the required intent in paragraph two of this instruction. (See
People v. Ocegueda (2016) 247 Cal.App.4th 1393, 1407 [203 Cal.Rptr.3d 233].)
The court may need to modify this instruction to ensure it does not prohibit the jury
from considering evidence of a defendant’s mental illness or impairment for a
purpose other than deciding whether defendant possessed the required mental state
for murder. (People v. McGehee (2016) 246 Cal.App.4th 1190, 1205 [201
Cal.Rptr.3d 714].) For example, giving this unmodified instruction with CALCRIM
No. 362, Consciousness of Guilt: False Statements, could be error if a defendant’s
false statements were the product of mental illness or impairment. (Ibid).
AUTHORITY
• Statutory Authority. Pen. Code, § 28; see also Pen. Code, §§ 25, 29.
• Instructional Requirements. People v. Saille (1991) 54 Cal.3d 1103, 1119 [2
Cal.Rptr.2d 364, 820 P.2d 588].
• Mental States - Knowledge. People v. Reyes (1997) 52 Cal.App.4th 975,
983-985 [61 Cal.Rptr.2d 39].
• Mental States - Aiding and Abetting. People v. Mendoza (1998) 18 Cal.4th 1114,
1131-1134 [77 Cal.Rptr.2d 428, 959 P.2d 735].
RELATED ISSUES
Scope of Expert Testimony
Penal Code section 29 provides that an expert testifying about a defendant’s mental
illness “shall not testify as to whether the defendant had or did not have the
required mental states.” (Pen. Code, § 29.) In People v. Coddington (2000) 23
Cal.4th 529, 582-583 [97 Cal.Rptr.2d 528, 2 P.3d 1081], disapproved on other
grounds in Price v. Superior Court (2001) 25 Cal.4th 1046, 1069, fn. 13 [108
Cal.Rptr.2d 409, 25 P.3d 618], the Supreme Court held that the trial court
improperly restricted the scope of the expert testimony when the court refused to
permit “hypothetical questions regarding the effect of mental defect or illness on a
person’s ability to deliberate or premeditate.” (Id. at p. 582.) “An expert’s opinion
that a form of mental illness can lead to impulsive behavior is relevant to the
existence vel non of the mental states of premeditation and deliberation regardless of
whether the expert believed appellant actually harbored those mental states at the
time of the killing.” (Id. at pp. 582-583 [italics original]; see also People v. Nunn
(1996) 50 Cal.App.4th 1357, 1364-1365 [58 Cal.Rptr.2d 294] [discussing
appropriate scope of expert testimony].)
SECONDARY SOURCES
1 Witkin & Epstein, California Criminal Law (4th ed. 2012) Defenses, § 9.
DEFENSES AND INSANITY CALCRIM No. 3428
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3 Millman, Sevilla & Tarlow, California Criminal Defense Practice, Ch. 73,
Defenses and Justifications, § 73.03 (Matthew Bender).
6 Millman, Sevilla & Tarlow, California Criminal Defense Practice, Ch. 124,
Jurisdiction and Disposition Hearings, § 124.04 (Matthew Bender).
CALCRIM No. 3428 DEFENSES AND INSANITY
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