with whom GLASSMAN, Justice, joins, concurring.
I agree that on this record the defendant did not establish that alcoholism entitled him to an insanity defense instruction. The evidence presented to the trial justice was that alcoholism “may be considered as a mental disease.” But the statute requires more. The term “ ‘mental disease or defect’ means only those severely abnormal mental conditions that grossly and demonstrably impair a person’s perception or understanding of reality.” 17-A M.R.S.A. § 39(2) (Supp.1988). The record supports the trial justice’s conclusion that the evidence would not justify a finding that this defendant’s alcoholism grossly and demonstrably impaired his perception or understanding of reality.
If the Court means to say that alcoholism per se could never qualify, however, I do not agree. The statute says: “An abnormality manifested only by ... excessive use of alcohol ..., in and of itself, does not constitute a mental disease or defect.” Id. By ordinary usage, excessive use of alcohol and alcoholism are not the same thing. If the medical science presented at trial shows that a defendant’s alcoholism is manifested by characteristics in addition to excessive use of alcohol and that it is a “severely abnormal” mental condition that “grossly and demonstrably impair[s]” his “perception or understanding of reality” 1 and that, as a result, “he lacked substantial capacity to appreciate the wrongfulness of his conduct,” then such a defendant is entitled to an insanity defense instruction under the statutory language the Leg*563islature has provided us.2 § 39(1) & (2) (Supp.1988). 17-A M.R.S.A.
In all other respects I join the Court’s opinion.
. The trial justice concluded that any gross abnormal perceptions of reality in this case resulted from intoxication, not alcoholism.
. There is no direct legislative history on Maine's language. Maine’s insanity defense generally was based on the opinion in United States v. Brawner, 471 F.2d 969 (D.C.Cir.1972); see L.D. 314 § 58 comment (107th Legis.1975), and Brawner had adopted the Model Penal Code formulation. 471 F.2d at 990-92. Maine’s exclusion of excessive use of alcohol seems to draw upon two provisions of the Model Penal Code: ”[i]ntoxication does not, in itself, constitute mental disease within the meaning of Section 4.01" and "the terms ‘mental disease or defect’ do not include an abnormality manifested only by repeated criminal or otherwise antisocial conduct.” Model Penal Code §§ 2.08(3) and 4.01(2) (Proposed Official Draft 1962). The Model Penal Code formulation contemplated adaptation to changing medical knowledge. According to the commentary as it was drafted in 1959:
There seems to be, at present, no clearly accepted concept of a psychosis giving rise to an uncontrollable urge to drink. On principle, if overindulgence in drink results from mental disease the actor would not be responsible if such drinking led to a lack of the capacities intrinsic to responsibility. In view of the divergence of medical opinion, however, the draft leaves the issue open for determination on the evidence that is adduced in a case where the point is raised under Section 4.01. The formulation does not preclude the defendant’s reliance on impairment of capacity due to intoxication which is in turn attributable to mental disease within the intendment of Section 4.01.
Model Penal Code § 2.08 (Tent. Draft No. 9 comment 5 May 8, 1959).