¶1In challenging a Muscogee County jury verdict finding him guilty of aggravated assault, Walter L. Gibson contends that he received ineffective assistance of counsel because his trial attorney (a) failed to raise the issue of Gibson’s alleged mental illness in relation to the voluntary nature of his confession; and (b) raised a defense of justification, instead of a defense of guilty but mentally ill. We find these contentions meritless.
¶2To show that trial counsel was ineffective, Gibson must show both that counsel’s performance was deficient and that the deficiency so prejudiced his defense that a reasonable probability exists that the outcome of trial would have been different but for the deficiency. Has-san v. State, 231 Ga. App. 783, 784 (500 SE2d 644) (1998).
¶3(a) During the Jackson/Denno
¶4(b) Equally meritless is Gibson’s contention that “trial counsel was ineffective in failing to raise the more plausible defense of guilty *573but mentally ill.” As the trial court noted, Gibson’s attorney could not raise a defense of mental illness when the existence of such alleged illness was neither manifest nor brought to the attorney’s attention in any fashion. Gibson, himself, maintained from the beginning that the victim was armed with a knife and thus his actions were justified. In light of his subsequent conviction, a mental illness defense may now appear to Gibson to be more “plausible,” but, as this Court has noted many times: “Effectiveness is not judged by hindsight or by the result” (Emphasis supplied.) Karvonen v. State, 205 Ga. App. 852, 853 (424 SE2d 47) (1992); Cauley v. State, 203 Ga. App. 299, 301 (2) (416 SE2d 575) (1992); Garrett v. State, 196 Ga. App. 872, 873 (1) (397 SE2d 205) (1990); Hosch v. State, 185 Ga. App. 71, 72 (2) (363 SE2d 258) (1987).
¶5Judgment affirmed.
¶6Jackson v. Denno, 378 U. S. 368 (84 SC 1774, 12 LE2d 908) (1964).
¶7 “The standard of effectiveness is not to be judged by hindsight nor by the result that the appellants were convicted.” Kervin v. State, 178 Ga. App. 601, 606 (344 SE2d 441) (1986). See also Solomon v. State, 247 Ga. 27, 28 (1) (277 SE2d 1) (1981) (“effective counsel does not mean errorless counsel and not counsel judged ineffective by hindsight”); Pitts v. Glass, 231 Ga. 638 (203 SE2d 515) (1974); Harrell v. State, 139 Ga. App. 556, 557 (2) (228 SE2d 723) (1976).