People v. Horn - 158 Cal. App. 3d 1014, 205 Cal. Rptr. 119 (1984)

Rule:

In order to be considered sane and therefore responsible for his actions, a defendant has to have the kind of knowledge that is relevant, namely an understanding or appreciation of the wrongfulness of his conduct. This knowledge has to be in relation to the very act with which the defendant is charged. Insanity, under the California M'Naghton test, denotes a mental condition which renders a person incapable of knowing or understanding the nature and quality of his act, or incapable of distinguishing right from wrong in relation to that act.

Facts:

A defendant charged with vehicular manslaughter entered pleas of not guilty and not guilty by reason of insanity. Defendant waived a jury trial, was found guilty, and during the sanity trial established beyond any doubt that she suffered from mental illness. The trial court indicated it would be prepared to find that at the time of the incident defendant was incapable of distinguishing between right and wrong by reason of her mental illness, but concluded that she had not sustained her burden of showing that she was also incapable of knowing the nature and quality of her act, and therefore ruled that she was not insane under Pen. Code, § 25, added by Proposition 8, the Victim's Bill of Rights. Under that 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." Defendant was sentenced to state prison.

Issue:

Should the defendant’s conviction be reversed by reason of insanity? 

Answer:

Yes.

Conclusion:

The court reversed the conviction because the trial court's express findings established that the defendant was legally insane under the M'Naghten test at the time of the incident. The court reviewed the history of the insanity defense and the events surrounding passage of Cal. Penal Code § 25(b), which statutorily defined the insanity defense. It determined that although the statute used the conjunctive "and," the test of insanity necessarily must use the disjunctive "or" form. It then determined that § 25(b) reinstated the California M'Naghten right and wrong test as the standard for the insanity defense. When it applied this test, the court determined that since the trial court held that defendant was incapable of distinguishing between right and wrong at the time of the incident, it expressly found the defendant met the second prong of the M'Naghten test and, therefore, defendant was entitled to a judgment of not guilty by reason of insanity.