Section 28 Of Title 1. Of Persons Liable To Punishment For Crime From California Penal Code >> Title 1. >> Part 1.
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. (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.