The legal defense of insanity in California law means that you cannot be found guilty of a crime if you were legally insane when you committed it.1 Under California’s insanity defense, you are considered legally insane if you either
- Did not understand the nature of your criminal act, OR
- Did not understand that what you were doing was morally wrong.2
This definition of legal insanity is known as the “McNaghten (sometimes spelled M’Naghten or McNaughten) rule.”3
You can plead not guilty by reason of insanity at your arraignment hearing. For the insanity defense to work, you will then need to prove that it is more likely than not that you were legally insane when you committed your crime.4
If you can convince the jury at your California criminal jury trial that you are not guilty by reason of insanity, then you will be committed to a state mental hospital instead of being sent to prison.5
Here are some examples of situations in which the legal defense of insanity could help a defendant get a verdict of not guilty:
- A woman who suffers from paranoid delusions is convinced that her neighbors have stolen her vacuum cleaner. She breaks into her neighbors’ house and takes their vacuum cleaner, which she believes is her own.She may be able to beat charges of California burglary with the insanity defense because she did not understand the nature of her act--she did not understand that she was taking someone else’s property.
- A schizophrenic man believes that God has entrusted him with the task of taking care of troubled children. After watching an 8-year-old boy fight with his mother in a grocery store, the man grabs the boy, shoves him in his car, and takes him out for an ice cream—thinking that he is helping the boy and fulfilling his God-given mission. When the man is later charged with kidnapping, he pleads not guilty by reason of insanity, because he did not understand that what he was doing was morally wrong.
In order to help you better understand the insanity defense, our California criminal defense attorneys6 will discuss the following:
- 1. The Legal Definition of Insanity in California (The McNaghten Test)
- 2. Proving Insanity as a Legal Defense in California
- 3. How to Enter a “Not Guilty by Reason of Insanity” Plea in California
- 4. Sentencing For the Legal Defense of Insanity
If, after reading this article, you would like more information, we invite you to contact us at Shouse Law Group.
1. The Legal Definition of Insanity (The McNaghten Test)
Under California law, a person is “legally insane”—and able to assert the legal defense of insanity—if, because of a mental illness, s/he EITHER
- Cannot understand the nature of his/her criminal act, OR
- Cannot distinguish between right and wrong.7
This legal definition of insanity is known as the McNaghten (sometimes spelled M’Naghten or McNaughten) rule.8 This interesting name comes from a 19th-century British defendant who is the basis for the following example:
Example: Daniel McNaghten suffers from paranoid delusions. He believes the government is out to get him. So in 1843 Daniel attempts to assassinate the Prime Minister of Britain and ends up shooting a government secretary instead.
Daniel is tried for attempted murder. But he is found not guilty because he is legally insane—that is, his mental illness makes him incapable of understanding that what he did was morally wrong.9
If a defendant’s mental state meets the McNaghten test, it doesn’t matter whether it was a permanent condition or a temporary one—even if it lasted only a few hours. Temporary insanity qualifies for the California insanity defense just as a permanent mental condition does.10
Despite all this, the number of mentally ill criminal defendants who actually plead not guilty by reason of insanity is quite low. Nationwide, only about one percent (1%) of all criminal defendants assert the insanity defense.11
Elizabeth’s depression caused her not to care about the consequences of the shoplifting. But it did not prevent her from understanding what she was doing. It also did not prevent her from understanding that the theft was morally wrong.
So even though Elizabeth’s mental illness contributed to her criminal activity, she was not legally insane when she shoplifted—and so she cannot assert the legal defense of insanity.
1.1. The McNaghten rule in California
California adopted the McNaghten rule as its legal definition of insanity when voters passed Proposition 8, known as the “Victim’s Bill of Rights,” in 1982.12
It is important to note that the California test for whether someone is legally insane only requires the defendant to prove that s/he was incapable of understanding the nature of his/her act OR that s/he was incapable of distinguishing right from wrong—not both.13
Example: Betty suffers from manic-depressive disorder. After filling up her gas tank, she drives away from the gas station without paying. A gas station attendant follows her on a motorcycle. Trying to escape him, Betty drives at over 80 mph and runs stoplights. Her reckless driving leads to an accident that kills another driver.
Betty is charged with vehicular manslaughter. She asserts the insanity defense. The jury decides that she WAS capable of understanding the nature of her actions—but was NOT capable of distinguishing right from wrong. Therefore, she is not guilty by reason of insanity.14
1.2. The insanity defense and drug addiction
Mental health problems and drug or alcohol addiction often go hand-in-hand. However, you may not assert the legal defense of insanity just because you
- Were addicted to drugs or alcohol when you committed the crime, or
- Had recently used drugs or alcohol when you committed the crime.15
Example: Jeffrey suffers from acid flashbacks due to his earlier extensive use of the drug LSD. These flashbacks cause him to hear voices that aren’t really there. When he is at a bar, he mistakenly believes that the bartender is threatening him and attacks the man. This leads to him getting charged with California assault.
Because Jeffrey’s delusions were due to the use of drugs rather than a non-drug-related mental condition, he cannot assert the insanity defense.16
However, if you were under the influence of drugs or alcohol when you committed a crime, the legal defenses of voluntary intoxication or involuntary intoxication may be of help to you.17
2. Proving Insanity as a Legal Defense in California
It is the defendant—and not the prosecutor—who bears what is called the “burden of proof” on the insanity defense.18
In most aspects of a criminal trial—including most importantly the basic question of guilt or innocence—the prosecutor has the burden of proof.19 But California’s insanity defense is what’s known as an “affirmative defense.”
As Riverside criminal defense lawyer Michael Scafiddi20 explains:
“An ‘affirmative defense’ is essentially a claim which the defendant makes that says ‘even though I committed the crime, my conduct should be excused for the following reason….’ In the case of the insanity defense, the reason is the defendant’s mental condition when she or he committed the crime.”
With an affirmative defense such as insanity, it is the defendant who must prove that s/he was insane at the time of the crime—and should therefore be excused from his/her criminal conduct.21
2.1. “Preponderance of the evidence” standard for the insanity defense
The defendant who pleads the insanity defense is required to prove that s/he was insane when the crime was committed by a “preponderance of the evidence. ”This means that s/he has to show that it is more likely than not that s/he was insane.22
Contrast this to the “beyond a reasonable doubt” standard of proof that the prosecution has to meet when it comes to the defendant’s guilt or innocence. “Beyond a reasonable doubt” means that the evidence is so strong that there is no logical explanation other than that the defendant is guilty.23
But even under the preponderance of evidence standard, if the jury feels that neither side has the stronger argument on the insanity defense—that is, if the evidence on both sides is equally strong—then they must rule against the defendant.24
3. How to Enter a “Not Guilty by Reason of Insanity” Plea in California
There are two ways to pursue an insanity defense. You can either
- Plead both “not guilty” and “not guilty by reason of insanity,” OR
- Admit that you committed the crime but plead “not guilty by reason of insanity.”25
3.1. Entering a “dual” plea of “not guilty” and “not guilty by reason of insanity”
The first way to enter a California insanity plea is to enter two pleas – one of “not guilty,” and a second of “not guilty by reason of insanity.”26
The first “not guilty” plea means that you did not actually commit the crime with which you were charged. The second plea means that you are asserting that—even if you did commit the crime—you should not be convicted because you were insane when you did so.
If you enter a dual plea, you will make your way through the California criminal court process as follows:
- The first step will be a trial that covers the question of your guilt/innocence—not the question of your sanity;
- If you are found not guilty, you go free, and the case is over; BUT
- If you are found guilty at this stage, the case proceeds to a hearing on your sanity that is called the “sanity trial.” This hearing may involve the same jury who ruled on your guilt/innocence, or a new jury. In the sanity trial, the court will decide whether you should be found not guilty by reason of insanity.27
This process is what is called a “bifurcated trial”—because the question of your guilt and the question of your sanity are dealt with in two separate proceedings.
3.2. Sanity hearings in California
During the sanity hearing, the defendant presents expert witnesses—usually psychiatrists—who testify that at the time of the offense, the defendant either
- didn’t understand the nature of his/her act, or
- didn’t understand that the act was wrong.28
These are the only issues that are relevant during the sanity trial.29
If the jury decides unanimously that the defendant was insane when s/he committed the crime, then s/he will be found not guilty by reason of insanity.30
The sanity hearing usually takes place before a jury—but not always. A judge may remove the issue of insanity from the jury if s/he feels that the defendant has failed to present sufficient evidence that they were insane when they committed the crime.31
Example: Victor is charged with aggravated California robbery. During his sanity hearing, he claims that he has suffered numerous blows to the head throughout his life—and that these have caused Satan to take over his body.
But the two psychologists who examine Victor testify that they believe he is making that up. The prosecution also presents a recording of a conversation in jail in which Victor tells his brother that he is “doing the homeless nut routine.”
The judge therefore concludes that there is not enough evidence that Victor is actually insane—and does not let the jury consider his insanity defense.32
3.3. Entering a single plea of “not guilty by reason of insanity”
In some cases, a defendant and his/her attorney may decide that it makes the most sense not to bother with a standard “not guilty” plea. Instead, the defendant concedes that s/he is guilty of the offense and only pleads the insanity defense.33
In these cases, the court proceeds directly to the sanity trial described in Section 3.2. There is no separate trial on guilt or innocence.34
4. Sentencing For the Legal Defense of Insanity
If you successfully plead the insanity defense, then you will not receive the normal jail/prison sentence for your crime. Instead, you will be committed to a state mental hospital.35
There are two reasons for commitment:
- to rehabilitate and treat the defendant, and
- to protect the defendant and society from further harm.36
The defendant must remain in the state mental hospital until:
- doctors believe that s/he has regained sanity,
- the maximum term of imprisonment for that crime has expired, or
- doctors believe s/he would do well in an outpatient treatment program instead.37
Call us for help…
If you or a loved one is in need of help using insanity as a legal defense and you are looking to hire an attorney for representation, we invite you to contact us at Shouse Law Group. We can provide a free consultation in office or by phone. We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California.
For more information on Nevada “insanity” laws, please see our page on Nevada “insanity” laws.
- Judicial Council of California Criminal Jury Instructions (“CALCRIM”) 3450 – Insanity: Determination, Effect of Verdict [California insanity defense]. (“If, after considering all the evidence, all twelve of you conclude the defendant has proved that it is more likely than not that (he/she) was legally insane when (he/she) committed the crime[s], you must return a verdict of not guilty by reason of insanity.”)
- See same. (“The defendant was legally insane if: 1 When (he/she) committed the crime[s], (he/she) had a mental disease or defect; AND 2 Because of that disease or defect, (he/she) was incapable of knowing or understanding the nature and quality of (his/her) act or was incapable of knowing or understanding that (his/her) act was morally or legally wrong.”)See also Penal Code 25 PC – Insanity as a California legal defense. (“… (b) In any criminal proceeding, including any juvenile court proceeding, in which a plea of not guilty by reason of insanity is entered, this defense shall be found by the trier of fact only when the accused person proves by a preponderance of the evidence that he or she was incapable of knowing or understanding the nature and quality of his or her act and of distinguishing right from wrong at the time of the commission of the offense.”)
- Black’s Law Dictionary (9th ed. 2009), McNaghten rules. (“The doctrine that a person is not criminally responsible for an act when a mental disability prevented the person from knowing either (1) the nature and quality of the act or (2) whether the act was right or wrong. The federal courts and most states have adopted this test in some form.”)
- CALCRIM 3450 – California insanity defense. (“The defendant must prove that it is more likely than not that (he/she) was legally insane when (he/she) committed the crime[s].”)
- People v. Dobson, (2008) 161 Cal.App.4th 1422, 1432. (“A successful insanity plea relieves the defendant of all criminal responsibility. (People v. Jantz (2006) 137 Cal.App.4th 1283, 1295, 40 Cal.Rptr.3d 875.) The commitment of the defendant to a state hospital “is in lieu of criminal punishment and is for the purpose of treatment, not punishment. [Citation.]” ( People v. Superior Court (Williams) (1991) 233 Cal.App.3d 477, 485, 284 Cal.Rptr. 601 ( Williams ).) “The purpose of committing an insanity acquittee is two-fold: to treat his mental illness and to protect him and society from his potential dangerousness. [Citation.]””)See also CALCRIM 3450 – California insanity defense. (“[If you find the defendant was legally insane at the time of (his/her) crime[s], (he/she) will not be released from custody until a court finds (he/she) qualifies for release under California law. Until that time (he/she) will remain in a mental hospital or outpatient treatment program, if appropriate.”)
- Our California criminal defense attorneys have local Los Angeles law offices in Beverly Hills, Burbank, Glendale, Lancaster, Long Beach, Los Angeles, Pasadena, Pomona, Torrance, Van Nuys, West Covina, and Whittier. We have additional law offices conveniently located throughout the state in Orange County, San Diego, Riverside, San Bernardino, Ventura, San Jose, Oakland, the San Francisco Bay area, and several nearby cities.
- Penal Code 25 PC – Insanity as a California legal defense, endnote 2, above.
- Black’s Law Dictionary (9th ed. 2009), McNaghten rules, endnote 3, above.
- See The McNaughton Rules, History of Forensic Psychology (blog).
- People v. Kelly, (1973) 10 Cal.3d 565, 576-577. (““…[t]emporary insanity as a defense to crime is as fully recognized by law as is permanent insanity.” (People v. Ford (1902) 138 Cal. 140, 141-142 [70 P. 1075].) Thus, if defendant at the time of the offense was insane under the California M’Naughton test, it makes no difference whether the period of insanity lasted several months, as in this case, or merely a period of hours.”)
- Julie Grachek, The Insanity Defense in the Twenty-First Century: How Recent United States Supreme Court Case Law Can Improve the System , 81 Ind. L. J. 1479, 1487-88 (2006).
- See People v. Horn, (1984) 158 Cal.App.3d 1014. (“But who is insane? In this case we explore that question by considering the type of showing which will support a finding of not guilty by reason of insanity under Penal Code section 25, subdivision (b), a new statute added to that code by the enactment of Proposition 8, the Victim’s Bill of Rights, at the June 1982 Primary Election. Under this statute, a defendant is insane only when “he or she was incapable of knowing or understanding the nature and quality of his or her act and of distinguishing right from wrong at the time of the commission of the offense.”)
- See same at 1031.
- Based on the facts of the same.
- CALCRIM 3450 – California insanity defense. (“[Special rules apply to an insanity defense involving drugs or alcohol. Addiction to or abuse of drugs or intoxicants, by itself, does not qualify as legal insanity. This is true even if the intoxicants cause organic brain damage or a settled mental disease or defect that lasts after the immediate effects of the intoxicants have worn off. Likewise, a temporary mental condition caused by the recent use of drugs or intoxicants is not legal insanity.]”)See also Penal Code 29.8 PC – Basis of defense; plea of not guilty by reason of insanity. (“In any criminal proceeding in which a plea of not guilty by reason of insanity is entered, this defense shall not be found by the trier of fact solely on the basis of a personality or adjustment disorder, a seizure disorder, or an addiction to, or abuse of, intoxicating substances. This section shall apply only to persons who utilize this defense on or after the operative date of the section.”)
- CALCRIM 3450 – California insanity defense, endnote 15, above.
- Penal Code 22 PC – Voluntary intoxication as an excuse for crime; admissibility of evidence [contrast to insanity defense]. (“Evidence of voluntary intoxication is admissible solely on the issue of whether or not the defendant actually formed a required specific intent, or, when charged with murder, whether the defendant premeditated, deliberated, or harbored express malice aforethought.”)See also People v. Heffington, (1973) 32 Cal.App.3d 1, 8. (“Unconsciousness due to involuntary intoxication is recognized as a complete defense to a criminal charge.”)
- Evidence Code 522 EC – Burden of proof on the insanity defense. (“The party claiming that any person, including himself, is or was insane has the burden of proof on that issue.”)
- California Jury Instructions, Criminal (CALJIC 2.90) — Presumption of Innocence-Reasonable Doubt-Burden of Proof [contrast with burden of proof for legal defense of insanity]. (“A defendant in a criminal action is presumed to be innocent until the contrary is proved, and in case of a reasonable doubt whether [his] [her] guilt is satisfactorily shown, [he] [she] is entitled to a verdict of not guilty. This presumption places upon the People the burden of proving [him] [her] guilty beyond a reasonable doubt. Reasonable doubt is defined as follows: It is not a mere possible doubt; because everything relating to human affairs is open to some possible or imaginary doubt. It is that state of the case which, after the entire comparison and consideration of all the evidence, leaves the minds of the jurors in that condition that they cannot say they feel an abiding conviction of the truth of the charge.”)
- Riverside criminal defense lawyer Michael Scafiddi, a former police officer and sergeant, represents clients in criminal cases ranging from DUI to child abuse to carjacking throughout the Inland Empire. He is an expert in all the major California legal defenses, including the insanity defense, and he is well-known at the criminal courts in Palm Springs,Hemet, Riverside, Barstow and Victorville.
- Evidence Code 522 EC – Burden of proof on the insanity defense, endnote 18, above.
- CALCRIM 3450 – California insanity defense. (“The defendant must prove that it is more likely than not that (he/she) was legally insane when (he/she) committed the crime[s].”)
- CALJIC 2.90 – Presumption of Innocence—Reasonable Doubt—Burden of Proof [contrast with a preponderance of evidence standard that applies to the insanity defense]. (“Reasonable doubt is defined as follows: It is not a mere possible doubt; because everything relating to human affairs is open to some possible or imaginary doubt. It is that state of the case which, after the entire comparison and consideration of all the evidence, leaves the minds of the jurors in that condition that they cannot say they feel an abiding conviction of the truth of the charge.”)
- CALJIC 2.50.2 – Definition of preponderance of the evidence [standard of proof for the insanity defense]. (““Preponderance of the evidence” means evidence that has more convincing force than that opposed to it. If the evidence is so evenly balanced that you are unable to find that the evidence on either side of an issue preponderates, your finding on that issue must be against the party who had the burden of proving it.”)
- Penal Code 1026 PC – Plea of insanity; separate trials; presumption of sanity; trial of sanity issue; verdict; sentence; confinement in state hospital or mental facility. (“(a) When a defendant pleads not guilty by reason of insanity, and also joins with it another plea or pleas, the defendant shall first be tried as if only such other plea or pleas had been entered, and in that trial the defendant shall be conclusively presumed to have been sane at the time the offense is alleged to have been committed. If the jury shall find the defendant guilty, or if the defendant pleads only not guilty by reason of insanity, then the question whether the defendant was sane or insane at the time the offense was committed shall be promptly tried, either before the same jury or before a new jury in the discretion of the court. In that trial, the jury shall return a verdict either that the defendant was sane at the time the offense was committed or was insane at the time the offense was committed. If the verdict or finding is that the defendant was sane at the time the offense was committed, the court shall sentence the defendant as provided by law. If the verdict or finding be that the defendant was insane at the time the offense was committed, the court, unless it shall appear to the court that the sanity of the defendant has been recovered fully, shall direct that the defendant be confined in a state hospital for the care and treatment of the mentally disordered or any other appropriate public or private treatment facility approved by the community program director, or the court may order the defendant placed on outpatient status pursuant to Title 15 (commencing with Section 1600) of Part 2.”)
- See same.
- See same.
- CALCRIM 3450 – California insanity defense, endnote 2, above.
- People v. Hernandez, (2000) 22 Cal.4th 512</a, 521. (“The “sanity trial is but a part of the same criminal proceeding as the guilt phase” (People v. Flores (1976) 55 Cal.App.3d 118, 122 [127 Cal.Rptr. 230]) but differs procedurally from the guilt phase of trial “in that the issue is confined to sanity and the burden is upon the defendant to prove by a preponderance of the evidence that he was insane at the time of the offense” ( id. at p. 121). As in the determination of guilt, the verdict of the jury must be unanimous. ( People v. Troche, supra, 206 Cal. at p. 44.)”)
- See same.
- People v. Severance, (2006) 138 Cal.App.4th 305, 316-317. (“Just as a criminal defendant may be “precluded from presenting to a jury defense such as unconsciousness [citation], diminished capacity [citation], [or] entrapment [citation], where there is insufficient evidence from which a reasonable jury could conclude that the particular facts underlying the instruction requested exist” ( People v. Mapp (1983) 150 Cal.App.3d 346, 350, 198 Cal. Rptr. 177), so a criminal defendant may be precluded, through the grant of a directed verdict, from presenting an insanity defense where the evidence is insufficient for a reasonable jury to find the defendant was insane at the time of his crimes.”)
- Based on the facts of the same.
- Penal Code 1026 PC – Plea of insanity, endnote 25, above.
- See same.
- See same.
- People v. Dobson. (2008) 161 Cal.App.4th 1422, 1432. (“A successful insanity plea relieves the defendant of all criminal responsibility. (People v. Jantz (2006) 137 Cal.App.4th 1283, 1295, 40 Cal.Rptr.3d 875.) The commitment of the defendant to a state hospital “is in lieu of criminal punishment and is for the purpose of treatment, not punishment. [Citation.]” ( People v. Superior Court (Williams) (1991) 233Cal.App.3d 477, 485, 284 Cal.Rptr. 601 ( Williams ).) “The purpose of committing an insanity acquittee is two-fold: to treat his mental illness and to protect him and society from his potential dangerousness. [Citation].”)
- See same at 1432. (“A defendant found not guilty by reason of insanity may be released from a state hospital upon either (1) the restoration of sanity pursuant to the provisions of section 1026.2; (2) expiration of the maximum term of commitment, which means “the longest term of imprisonment which could have been imposed for the offense or offenses of which the person was convicted” (§ 1026.5, subd. (a)(1)); or (3) approval of outpatient status pursuant to the provisions of section 1600 et seq. (§ 1026.1; see People v. Soiu (2003) 106 Cal.App.4th 1191, 1194-1195, 131 Cal.Rptr.2d 421 ( Soiu ).)”)