We consider first the assignment of error which challenges the court’s ruling that defendant when arraigned and tried had sufficient mental capacity to plead to the indictments and to conduct a rational defense.
“In determining a defendant’s capacity to stand trial, the test is whether he has the capacity to comprehend his position, to understand the nature and object of the proceedings against him, to conduct his defense in a rational manner, and to cooperate with his counsel to the end that any available defense may be interposed.” 21 Am. Jur. 2d, Criminal Law § 63 (1965) ; accord, State v. Propst, 274 N.C. 62, 70, 161 S.E. 2d 560, 566 (1968) ; State v. Jones, 278 N.C. 259, 266, 179 S.E. 2d 433, 438 (1971); 2 Strong, N. C. Index 2d, Criminal Law § 29.
The uncontradicted evidence is to the effect that, when tested by the rule stated above, defendant had sufficient mental capacity to plead to the indictments and conduct a rational defense. Assuming, arguendo, he had such mental capacity at the time of his arraignment and trial, defendant contends it was dependent upon his continued use of prescribed medication to control the psychotic symptoms of a paranoid schizophrenic. Defendant refers to mental capacity under these circumstances as “synthetic sanity” and asserts such a person is mentally incapable of pleading to the indictment and conducting a rational defense.
The Supreme Court of Louisiana considered and rejected the precise contention now made by defendant. The Louisiana statute provided: “Mental incapacity to proceed exists when, as a result of mental disease or defect, a defendant presently lacks the capacity to understand the proceedings against him or to assist in his defense.” In State v. Plaisance, 252 La. 212, 210 So. 2d 323 (1968), and in State v. Hampton, 253 La. 399, 218 So. 2d 311 (1969), the defendant asserted he was mentally *248incapable of pleading and of standing trial in that his “sanity” was “synthetic” because of circumstances closely analogous to those disclosed by the evidence in the present case. Speaking for the Supreme Court of Louisiana, Justice (now Chief Justice) Sanders, in Hampton, said:
“The test of present insanity under the above Article is whether the defendant presently lacks the capacity to understand the proceedings or to assist in the defense. A defendant who is capable of understanding the nature and object of the proceedings and assisting rationally in the defense is competent to stand trial. [Citations omitted.]
“The members of the sanity commission were the only witnesses to testify at the hearing. In their opinion, defendant can understand the nature of the proceedings and assist in her defense. The record contains no evidence to the contrary. The psychotic symptoms are in remission. That this condition has resulted from the use of a prescribed tranquilizing medication is of no legal consequence. Under the codal test, the court looks to the condition only. It does not look beyond existing competency and erase improvement produced by medical science.” State v. Hampton, supra, at 403, 218 So. 2d at 312. Cf. State v. Hancock, 247 Or. 21, 426 P. 2d 872 (1967) ; State v. Rand, 20 Ohio Misc. 98, 247 N.E. 2d 342 (1969).
 The sole question now under consideration is whether defendant was capable of pleading and standing trial at the time of his arraignment and trial. All the evidence tends to show he had sufficient mental capacity at that time to meet the prescribed test. Hence, the court’s ruling was proper.
We consider now the assignment of error which challenges the court’s denial of defendant’s motion at the conclusion of all the evidence for judgment as in case of nonsuit. Defendant’s position is based largely on the fact that his mental condition was diagnosed “paranoid schizophrenia” and on Dr. Maynard’s testimony (on voir dire) that he knew of no cure for schizophrenia or paranoia, although both could be brought into remission by medication. The contention seems to be that a person who has the mental condition or disease diagnosed as “paranoid schizophrenia” lacks legal responsibility for conduct which constitutes a violation of the criminal law when committed by a “normal” person and therefore is not guilty as a matter of law.
*249In view of the recurrence of trials in which the mental condition of the defendant is diagnosed as “schizophrenia” or “paranoia” or “paranoid schizophrenia,” we have set forth the evidence in greater detail to indicate the legal problems these cases present to the jury and to the court.
Defendant’s contention that he is exempt from criminal responsibility as a matter of law by reason of mental disease ignores the well established legal test for determining whether a person is exempt from criminal responsibility by reason of insanity. In State v. Swink, 229 N.C. 123, 125, 47 S.E. 2d 852, 853 (1948), Ervin, J., restated the rule in this jurisdiction as follows: “ [A] n accused is legally insane and exempt from criminal responsibility by reason thereof if he commits an act which would otherwise be punishable as a crime, and at the time of so doing is laboring under such a defect of reason, from disease of the mind, as to be incapable of knowing the nature and quality of the act he is doing, or, if he does know this, incapable of distinguishing between right and wrong in relation to such act.” Subsequent decisions in accord therewith include the following: State v. Creech, 229 N.C. 662, 674, 51 S.E. 2d 348, 357 (1949); State v. Spence, 271 N.C. 23, 38, 155 S.E. 2d 802, 814 (1967) ; State v. Jones, 278 N.C. 259, 266, 179 S.E. 2d 433, 438 (1971) ; State v. Humphrey, 283 N.C. 570, 573-74, 196 S.E. 2d 516, 518-19 (1973) ; State v. Helms, 284 N.C. 508, 513, 201 S.E. 2d 850, 853-54 (1974). Insanity is incapacity, from disease of the mind, to know the nature and quality of one’s act or to distinguish between right and wrong in relation thereto. State v. Mercer, 275 N.C. 108, 117, 165 S.E. 2d 328, 335 (1969) ; State v. Atkinson, 275 N.C. 288, 313-14, 167 S.E. 2d 241, 256 (1969) ; 2 Strong’s N. C. Index 2d, Criminal Law § 5.
When a defendant in a criminal case pleads insanity, the applicable rule with reference to the burden of proof on this issue has been well stated as follows: “Since soundness of mind is the natural and normal condition of men, everyone is presumed to be sane until the contrary is made to appear. This presumption of sanity applies to persons charged with crime, but it is rebuttable. [Citations omitted.] These considerations give rise to the firmly established rule that the burden of proof upon a plea of insanity in a criminal case rests upon the accused who sets it up. But he is not obliged to establish such plea beyond a reasonable doubt. He is merely required to prove his insanity to the satisfaction of the jury. [Citations omitted.]” State v. Swink, supra, at 125, 47 S.E. 2d at 853.
*250Dr. Maynard testified that “every schizophrenic is an individual”; that “some clearly know right from wrong and . . . some don’t”; and that, in his opinion, defendant knew the difference between right and wrong on 29 December 1972, the date of the alleged crime (s), without regard to whether he was then under medication. However, the opinion of an expert psychiatrist is not conclusive. As noted in In re Tew, 280 N.C. 612, 619, 187 S.E. 2d 18, 18 (1972) : “Psychiatry is not an exact science. . . .” Here, in addition to Dr. Maynard’s expert testimony, the evidence includes testimony of significant facts bearing upon whether defendant was criminally responsible on 29 December 1972.
The testimony of Hall and Harrell tends to portray defendant as a somewhat nervous person; that defendant entered the store at night at a time when no one was there except the two cashiers; that he got his bearings while making inquiry and getting advice concerning a job; that he wanted all the cash but no checks; and that before walking out he warned the employee (s) of the store not to follow him. Their testimony tends to show a planned robbery, executed with finesse. In their opinion, defendant appeared to be in his right mind. There is no evidence that defendant had identified himself with Jesse James prior to his entering Cherry Hospital on 6 February 1973. The facts recited by him to Dr. Maynard do not point to any incident in which he contributed to the poor the fruits of any robbery or theft he committed.
There was evidence tending to show that, when arrested and advised of his constitutional rights, defendant made no statement except to say that he wanted a lawyer; and that, when brought from Wake jail to Wayne jail, defendant appeared to be in his right mind.
There was evidence tending to show that on the morning of his trial he called upon his father to testify that he was crazy. Too, it might be inferred that his outburst at trial, considered in the light of the evidence that he had not previously shown hostility toward Maynard, was a calculated attempt to convey the impression that he was insane.
 We hold that diagnosis of a defendant’s mental condition or disease as “paranoid schizophrenia,” standing alone, does not exempt him from legal responsibility for criminal conduct; that he is exempt only if insane when tested by the rule stated above; *251and that expert testimony in respect of his mental condition or disease is for consideration by the jury along with all other evidence pertinent to the issue raised by the plea of insanity.
The jury decided the issue of insanity against this defendant and found him guilty of the crime (s) charged in the indictments. The evidence fully warranted this verdict.
We have considered above the questions discussed by defendant in his supplemental brief. We refrain from discussing defendant’s numerous assignments of error involving rulings on evidence and portions of the court’s charge. Suffice to say, we approve the discussion and disposition thereof by Judge Baley in his opinion for the Court of Appeals. Hence, in accord with the Court of Appeals, we find no error with reference to the trial and verdicts.
Defendant has presented in this Court the contention that there was a single robbery and that the verdict (s) will support only one judgment for violation of G.S. 14-87. Although this question was not presented to or discussed by the Court of Appeals, consideration thereof is deemed appropriate since two judgments were pronounced, each imposing a prison sentence of not less than twenty nor more than twenty-five years, with provision that these sentences are to run consecutively.
Each indictment refers to the felonious taking of $265.00 on 29 December 1972. Neither alleges the ownership of the $265.00 to which it refers. Although the reading of the two indictments, side by side, leaves the impression each refers to the same $265.00, and that Hall and Harrell were robbed on the same occasion, neither refers to the other. Each indictment is complete.
The evidence discloses all of the $265.00 defendant obtained from Hall and Harrell belonged to the Food Market, their employer; and that, on the same occasion, and in the immediate presence of both, defendant, by the threatened use of a revolver, first obtained from Hall the cash in register No. 1 and immediately thereafter obtained from Harrell the cash in register No. 2. Although we find no evidence that defendant actually pointed the revolver at Hall or at Harrell, each was put in fear by defendant’s threatened use of the revolver. Neither Hall nor Harrell was physically injured in any manner.
The evidence indicates that, when the robbery occurred, Hall had immediate charge of register No. 1 and Harrell had *252immediate charge of register No. 2. However, the cash in both registers belonged to their employer. Both Hall and Harrell had custody thereof for their employer and the right to retain possession of all of it against robbery or theft.
In the light of the evidence, we hold that the verdicts have the same effect as if defendant had been found guilty after trial on a single indictment which charged the armed robbery of Hall and Harrell on 29 December 1972 in which $265.00 of the money of Food Market, their employer, had been taken from their persons and presence.
In State v. Ballard, 280 N.C. 479, 490, 186 S.E. 2d 372, 378 (1972), it is stated: “This case is of first impression in this jurisdiction involving a factual situation in which several employees of a store or other place of business are confronted by armed robbers and the life of each employee is endangered and threatened.”
In Ballard the defendant was indicted for armed robbery involving the theft of $1501.17 of money belonging to the Great Atlantic and Pacific Tea Company, Inc. The first of two trials was on an indictment which charged, inter alia, that the robbery was committed by the use or threatened use of a .38-caliber pistol whereby the “life of Kane Parsons” was threatened and endangered and the $1501.17 was taken from the “person of Kane Parsons.” Evidence disclosed that, although Parsons was an employee and in the store when the robbery occurred, the money was actually taken from his fellow employees, namely, Pat Britt and Nolan Smith. Nonsuit was allowed for variance between the indictment and proof. The second trial was upon a new indictment in all respects the same as the first except it alleged that the “lives of Pat Britt and Nolan Smith” were endangered and threatened, and the $1501.17 was taken “from the presence and person of Pat Britt and Nolan Smith.”
Defendant was convicted and sentenced. This Court reversed, holding the nonsuit (acquittal) at the first trial precluded further prosecution.
In reaching this conclusion, the Court stated: “Clearly, both indictments and the evidence at both trials relate to what occurred on the same occasion, namely, the robbery of the A & P store on August 21, 1970, allegedly by defendant and two others, perpetrated by endangering and threatening the lives of all employees then present. The evidence, on which Ballard was *253convicted at the second trial, tended to show that Ballard was one of three men who entered the store about 8:55 p.m. on August 21, 1970; that Ballard and one of his confederates were armed with and displayed pistols; that, in the perpetration of their crime, the robbers commanded all employees to ‘freeze’ and for everybody to ‘hit the floor,’ which commands were promptly obeyed; that the employees in the store who heard and obeyed these commands included Pat Britt, Nolan Smith and Kane Parsons; that, although the money was removed from the immediate presence of Pat Britt and Nolan Smith, all employees in the store were confronted by the robbers and had responsibility for the custody and care of the employer’s money; and that the life of each was threatened and would have been further endangered if any one or more of these employees had offered resistance to the armed robbers. We have concluded that this evidence was sufficient to have sustained the conviction of Ballard at the first trial and that the termination thereof in his favor supports his plea of double jeopardy.
“The duty of Kane Parsons to his employer would have required him to intervene to protect the property if he could have done so without further endangering his life. (Kane Parsons testified on voir dire that he was the assistant manager of this A & P store.) The fact that he happened to be farther from the property than Pat Britt and Nolan Smith when it was actually taken into possession by the robbers does not negate the fact it was taken from the presence of Parsons and all other employees then on duty in the store.”
In Ballard, as in the case at hand, no physical injury was inflicted on any employee. Nor was any property taken except that of the employer.
 Although double jeopardy and collateral estoppel are not directly involved in the present case, the rationale of Ballard is that, when the lives of all employees in a store are threatened and endangered by the use or threatened use of a firearm incident to the theft of their employer’s money or property, a single robbery with firearms is committed.
We express no opinion as to factual situations in which, in addition to robbery, an employee is physically injured or killed, or to factual situations in which, in addition to the theft of the employer’s money or property, the robber takes money or property of an employee or customer.
*254The foregoing leads to these conclusions: We find no error in the trial and uphold the verdicts. However, the two verdicts are to be considered the same as a single verdict of guilty of armed robbery. The judgments pronounced are to be considered as if a single judgment were pronounced which imposed a prison sentence of not less than twenty nor more than twenty-five years, subject to credit for time in jail prior to trial. The judgments are so modified.
The cause is remanded to the Court of Appeals with direction to remand to the Superior Court of Wayne County with direction to that court to withdraw its prior commitment (s) and issue a new commitment in conformity with this decision.
No error in trial.
Judgment modified and cause remanded.