Title 1. Of Persons Liable To Punishment For Crime of California Penal Code >> Title 1. >> Part 1.

(a) The defense of diminished capacity is hereby abolished. In a criminal action, as well as any juvenile court proceeding, evidence concerning an accused person's intoxication, trauma, mental illness, disease, or defect shall not be admissible to show or negate capacity to form the particular purpose, intent, motive, malice aforethought, knowledge, or other mental state required for the commission of the crime charged.
  (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.
  (c) Notwithstanding the foregoing, evidence of diminished capacity or of a mental disorder may be considered by the court only at the time of sentencing or other disposition or commitment.
  (d) The provisions of this section shall not be amended by the Legislature except by statute passed in each house by rollcall vote entered in the journal, two-thirds of the membership concurring, or by a statute that becomes effective only when approved by the electors.

All persons are capable of committing crimes except those belonging to the following classes: One--Children under the age of 14, in the absence of clear proof that at the time of committing the act charged against them, they knew its wrongfulness. Two--Persons who are mentally incapacitated. Three--Persons who committed the act or made the omission charged under an ignorance or mistake of fact, which disproves any criminal intent. Four--Persons who committed the act charged without being conscious thereof. Five--Persons who committed the act or made the omission charged through misfortune or by accident, when it appears that there was no evil design, intention, or culpable negligence. Six--Persons (unless the crime be punishable with death) who committed the act or made the omission charged under threats or menaces sufficient to show that they had reasonable cause to and did believe their lives would be endangered if they refused.

(a) The following persons are liable to punishment under the laws of this state:
  (1) All persons who commit, in whole or in part, any crime within this state.
  (2) All who commit any offense without this state which, if committed within this state, would be larceny, carjacking, robbery, or embezzlement under the laws of this state, and bring the property stolen or embezzled, or any part of it, or are found with it, or any part of it, within this state.
  (3) All who, being without this state, cause or aid, advise or encourage, another person to commit a crime within this state, and are afterwards found therein.
  (b) Perjury, in violation of Section 118, is punishable also when committed outside of California to the extent provided in Section 118.

(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.

In the guilt phase of a criminal action, any expert testifying about a defendant's mental illness, mental disorder, or mental defect shall not testify as to whether the defendant had or did not have the required mental states, which include, but are not limited to, purpose, intent, knowledge, or malice aforethought, for the crimes charged. The question as to whether the defendant had or did not have the required mental states shall be decided by the trier of fact.

(a) The intent or intention is manifested by the circumstances connected with the offense.
  (b) In the guilt phase of a criminal action or a juvenile adjudication hearing, evidence that the accused lacked the capacity or ability to control his or her conduct for any reason shall not be admissible on the issue of whether the accused actually had any mental state with respect to the commission of any crime. This subdivision is not applicable to Section 26.

(a) No act committed by a person while in a state of voluntary intoxication is less criminal by reason of his or her having been in that condition. Evidence of voluntary intoxication shall not be admitted to negate the capacity to form any mental states for the crimes charged, including, but not limited to, purpose, intent, knowledge, premeditation, deliberation, or malice aforethought, with which the accused committed the act.
  (b) 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.
  (c) Voluntary intoxication includes the voluntary ingestion, injection, or taking by any other means of any intoxicating liquor, drug, or other substance.

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.