To establish the defense of insanity, it must be shown that:

     (1) At the time of the commission of the offense, as a result of mental disease or defect, the mind of the actor was affected to such an extent that:

     (a) He or she was unable to perceive the nature and quality of the act with which he or she is charged; or

     (b) He or she was unable to tell right from wrong with reference to the particular act charged.

     (2) The defense of insanity must be established by a preponderance of the evidence.

[2011 c 336 § 353; 1975 1st ex.s. c 260 § 9A.12.010.]