Section 25 Of Title 1. Of Persons Liable To Punishment For Crime From California Penal Code >> Title 1. >> Part 1.
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. (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.