(1) A person is guilty except for insanity if, at the time of engaging in criminal conduct, the person lacks substantial capacity either to appreciate the criminality of the conduct or to conform the conduct to the requirements of law, and:
(a) But for a qualifying mental disorder, the person would have had such substantial capacity;
(b) A mental disorder other than a qualifying mental disorder is not the primary cause of the lack of substantial capacity; and
(c) The lack of substantial capacity is not the result of voluntary intoxication in combination with a qualifying mental disorder, a mental disorder other than a qualifying mental disorder or both.
(2) As used in chapter 743, Oregon Laws 1971, the term “qualifying mental disorder” does not include an abnormality manifested only by repeated criminal or otherwise antisocial conduct, nor does the term include any abnormality constituting solely a personality disorder.