It is a defense to criminal liability if you can show that you were insane at the time the crime was allegedly committed. To be considered legally insane for this purpose you have to show that you had a mental infirmity, disease, or defect AND that, because of this condition, you did not know what you were doing or the consequences of doing it OR if you did know what you were doing and the consequences of doing it, that you did not know it was wrong.
The law presumes all of us to be sane. So you, as the defendant, have the burden of proving insanity by clear and convincing evidence. Clear and convincing means enough evidence that is precise, explicit, lacking in confusion, and of such weight that it produces a firm belief, without hesitation, about the matter in issue.
In presenting this defense, you can call expert and non-expert witnesses. What matters is whether you were “insane” when the crime was committed – not whether you are insane now or at another point in the past.
Losing control because of passion or temper will not be considered insanity, even though the normal judgment of the person can be overcome by passion or temper.
Even if the jury finds that you were guilty of the offense(s) beyond a reasonable doubt, but they find you insane by clear and convincing evidence, they must find you not guilty by reason of insanity. However, keep in mind that just because you may be found not guilty by reason of insanity, that does not mean you will be free to go. You may be committed to a mental hospital or turned over to an outpatient treatment facility instead.