The dispositive issue in this appeal is who has the burden of proof on the issue of drug dependency in a case charging sale of a narcotic substance by a person who is not drug-dependent.
The defendant, Veronica Hart, was charged in a four count information with: (1) sale of a narcotic substance by a person who is not drug-dependent in violation of General Statutes § 21a-278 (b)1; (2) sale of a narcotic substance in violation of General Statutes § 21a-277 (a)2; (3) conspiracy to sell a narcotic substance *598in violation of General Statutes §§ 21a-277 (a) and 58a-48 (a)* 3; and (4) possession of a narcotic substance in violation of General Statutes § 21a-279 (a).4 The defendant was tried jointly with another accused, John Cavanaugh. Following her conviction by a jury of all of the above counts, the defendant appealed to the Appellate Court. In State v. Hart, 23 Conn. App. 746, 585 A.2d 103 (1991), the Appellate Court reversed her conviction of sale of narcotics by a person who is not drug-dependent because it concluded that the state failed to prove beyond a reasonable doubt that the defendant was not drug-dependent, and that the trial court improperly allowed the jury to determine whether the issue of drug dependency had been raised.
We granted the state’s petition for certification to appeal from the decision of the Appellate Court; State v. Hart, 217 Conn. 811-12, 587 A.2d 152 (1991); limited to the following three questions: “1. Did the Appellate Court correctly rule that the state may not satisfy its burden of proving the defendant is not drug-dependent *599by destroying the credibility of defense witnesses, even though drug dependency is not an element of General Statutes § 21a-278 (b)? 2. Was the Appellate Court correct in not considering facts elicited by the state during cross-examination when it determined there was insufficient evidence of non-drug dependency? 3. Did the Appellate Court correctly conclude that the trial court’s instructions were erroneous because it instructed the jury to determine whether the defendant’s evidence of drug dependency was credible?”5 We conclude that the Appellate Court incorrectly ruled on the first and second certified questions, and improperly ordered the trial court to acquit the defendant of a violation of § 21a-278 (b).
The opinion of the Appellate Court accurately reports the relevant facts. State v. Hart, supra, 23 Conn. App. 748. For the purposes of this case, we note the following. Stephen Cahill and Paul Yanderheiden were police officers affiliated with the statewide narcotics task force. On the evening of October 23, 1986, Cahill and Vanderheiden traveled to the 190 East Cafe in Enfield where they had been assigned to complete an undercover narcotics enforcement operation. Upon his arrival at the bar, Cahill made it known to various persons that he was interested in purchasing narcotics. While Cahill was seated in a corner of the bar, the defendant approached him and stated that she had heard that he *600was interested in purchasing some cocaine. The defendant told Cahill that if he would give her $50 she would obtain a gram of cocaine from Cavanaugh, a bouncer at the bar, which she would divide with Cahill. After Cahill gave the defendant the money, she approached Cavanaugh and transferred the money to him. In return, Cavanaugh gave the defendant a packet containing approximately one gram of cocaine. She then returned to Cahill, and the two left the bar and divided the cocaine in Cahill’s car.
The jury also heard evidence indicating that the defendant was drug-dependent at the time of the charged offenses. Joni Zarcaro testified that she had known the defendant at the time of the charged offenses, and that she had witnessed the defendant use cocaine two or three times a week. Elizabeth Ann Donahue stated that she also knew the defendant at the time of the charged offenses and that for as long as she had known her, the defendant had admitted that she had a drug problem. Donahue testified that she had advised the defendant to seek drug treatment, but was not aware that the defendant had ever done so, and she believed that the defendant still had a drug problem at the time of trial. David Lombardi also testified that he had known the defendant at the time of the charged offenses. Lombardi stated that when he was with the defendant and drugs were available, which was “pretty much all the time,” the defendant would invariably try to acquire the drugs. He testified that he had observed the defendant use both cocaine and marihuana, and that he had personally used cocaine with the defendant five hundred times over the four or five years he had known her. Lombardi testified that, in 1986 and 1987, the defendant had sometimes complained that she could not go to work because of drug use, and he had heard her say that she “needed cocaine.” Lombardi testified that *601he had seen the defendant in bars, in malls and around town when she appeared to be intoxicated, either on drugs or alcohol.
Further, Lawrence Weiner, a psychiatrist, testified as an expert witness. He stated that he had met with the defendant in November, 1988, and completed a drug dependency evaluation of her at that time. He testified that the defendant had told him that, at the time of the charged offenses, she was using cocaine intranasally. Weiner also testified that the defendant told him that she began using cocaine on a daily basis in late 1987, and that, from that time forward, she spent $50 a day on cocaine. Weiner stated that the defendant told him that she used all the money she had remaining after buying food and paying rent to purchase cocaine. He also testified that the defendant had told him that in 1987 and 1988, she suffered from symptoms of cocaine withdrawal, including a craving for cocaine, and depression. He additionally stated that the defendant had reported to him that she had tried to stop using cocaine, but had not been successful. Weiner concluded that the defendant had used cocaine episodically prior to November, 1987. Weiner testified that, as a result of the evaluation, he diagnosed the defendant as having a dependence on both cocaine and alcohol at the time the charged offenses were committed.
The state conducted cross-examination of all of the above witnesses. Zarcaro admitted that she had seen the defendant many times inside bars, sometimes for four hours or more, but that she had never actually observed the defendant using drugs. Similarly, Donahue stated that she had never actually been in the presence of the defendant when the defendant was using drugs. Lombardi also stated that he saw the defendant in bars three or four times a week in the fall of 1986. He testified that, although he had seen the defendant at the 190 East Cafe for periods of up to eight hours, *602he had never actually witnessed her use drugs in the bar. Further, Lombardi stated that when the defendant had come to his house to use drugs, she would sometimes share her cocaine with other people. Lombardi stated that the most cocaine he had ever seen the defendant bring was about one-half gram, although she might actually have had more that he did not see. Lombardi also stated that, at the time of the charged offenses, the defendant was steadily employed, although there were days when she could not go to work because of drug use. Lombardi further admitted that he had seen the defendant stay in bars for six to eight hours and never heard her say that she needed cocaine.
In the course of the state’s cross-examination, Weiner admitted that all of his findings were based upon a forty-five minute interview with the defendant in 1988, two years after the charged offenses had allegedly occurred. Weiner conceded that he had failed to perform a physical examination of the defendant and that, although he concluded that the defendant used cocaine intranasally, which could cause physical damage to the nose, he had never examined the defendant’s nose to determine whether there was any indication of cocaine use. Weiner also testified that the defendant had stated to him that she had only occasionally used cocaine, once or twice a week, at the time of the charged offenses, and did not begin using cocaine daily until late in 1987. Weiner stated that he recalled that the defendant had told him that she was always able to hold a job. Finally, Weiner admitted that his evaluation of the defendant and his conclusions about her drug use were based solely on information he had obtained from her.
I
We first address the state’s claim that the Appellate Court incorrectly ruled that the state failed to disprove drug dependency beyond a reasonable doubt. The state *603claims that the Appellate Court improperly failed to consider facts elicited by the state on cross-examination,6 and improperly held that the state may not satisfy its burden solely by discrediting the defendant’s evidence. The state claims that its cross-examination proved beyond a reasonable doubt that the defendant was not drug-dependent. We disagree.
At trial, as noted, the defendant offered testimony through Zarcaro, Donahue, Lombardi and Weiner indicating that she was drug-dependent at the time of the charged offenses.7 The state cross-examined all of the defense witnesses. The trial court, in its charge, informed the jury that it could properly find that the state’s cross-examination proved beyond a reasonable *604doubt that the defendant was not drug-dependent.8 The Appellate Court, however, concluded that the state’s evidence did not disprove drug dependency beyond a reasonable doubt because no affirmative evidence was elicited on cross-examination and, “while a jury may reject a witness’ testimony, it may not conclude from that rejection that the opposite is true. State v. Coleman, 14 Conn. App. 657, 671-76, 544 A.2d 194, cert. denied, 208 Conn. 815, 546 A.2d 283 (1988).” State v. Hart, supra, 23 Conn. App. 755-56.
A
The state argues that it proved beyond a reasonable doubt that the defendant was not drug-dependent because the jury may have so disbelieved the testimony of the defense witnesses as to infer the opposite of their testimony. We do not agree.
It is without question that the jury is the ultimate arbiter of fact and credibility. State v. Dyson, 217 Conn. 498, 506, 586 A.2d 610 (1991). As such, it may believe or disbelieve all or any portion of the testimony offered. *605Upon review of a defendant’s claim that there was insufficient evidence to support his conviction, we view the evidence in the light most favorable to the state. State v. Carpenter, 214 Conn. 77, 78, 570 A.2d 203 (1990). In the course of that analysis, we assume that the jury credited the evidence favorable to the state and discredited the evidence favorable to the defendant. We have consistently stated, however, that the jury may not infer the opposite of a witness’ testimony solely from its disbelief of that testimony. State v. Carter, 196 Conn. 36, 50, 490 A.2d 1000 (1985); State v. Alfonso, 195 Conn. 624, 634, 490 A.2d 75 (1985); Novak v. Anderson, 178 Conn. 506, 508, 423 A.2d 147 (1979); State v. Coleman, supra, 671-78.
The state argues that the jury should be allowed to infer the opposite of the defense testimony in this case because the defendant did not testify and because the absence of drug dependency is not an element of the state’s case. The Appellate Court has concluded that an instruction allowing the jury to infer the opposite of the defendant’s testimony impermissibly burdens his fifth and fourteenth amendment right to testify in his own defense. State v. Coleman, supra, 675. Although a request that the jury infer the opposite of a criminal defendant’s testimony may raise additional constitutional questions, we have not limited the rule to circumstances involving the testimony of a criminal defendant. State v. Carter, supra; Marquis v. Drost, 155 Conn. 327, 332, 231 A.2d 527 (1967); Edwards v. Grace Hospital Society, 130 Conn. 568, 574-75, 36 A.2d 273 (1944). Furthermore, whether the issue in contention is an element of a criminal offense is not dispositive. Our rule barring the inference of the opposite of testimony has been applied uniformly in both criminal and civil contexts. State v. Carter, supra; State v. Alfonso, supra; Novak v. Anderson, supra; Marquis v. Drost, supra. It is an evidentiary issue concerning the *606proper method of measuring the sufficiency of the evidence. The distinction between elements and nonelements of a crime, in this particular context, is inconsequential. Accordingly, we conclude that the state could not prove beyond a reasonable doubt that the defendant was not drug-dependent through impermissible inferences of the opposite of testimony favorable to the defense.
B
The state next asserts that it elicited sufficient affirmative evidence of the nonexistence of drug dependency through cross-examination to prove beyond a reasonable doubt that the defendant was not drug-dependent at the time of the charged offenses. We do not agree.
In the course of its cross-examination, the state elicited information that tended to prove that the defendant was not drug-dependent at the time of the charged offense. Importantly, Weiner admitted that the defendant had told him that, at the time of the offense, she used drugs only occasionally. Further, the state elicited testimony that the defendant had been steadily employed, and that her use of cocaine did not escalate to the level of a daily habit until November, 1987. Zarcaro, Lombardi and Donahue all stated that they had never actually witnessed the defendant using drugs in a bar, although they had seen her in bars regularly. Moreover, Weiner testified that even after the defendant had begun using cocaine on a daily basis, she had not spent an excessive amount of time planning to get it, taking it or recovering from its effects. This evidence was probative of the state’s assertion that the defendant was not drug-dependent at the time of the offense. Contrary to the opinion of the Appellate Court, the state’s cross-examination was not limited to an *607attack on the credibility of the defense witnesses.9 The Appellate Court, therefore, improperly ruled that the state elicited no affirmative evidence on cross-examination. The evidence that it did elicit, however, as a matter of law, was not sufficient to prove beyond a reasonable doubt that the defendant was not drug-dependent at the time of the offenses. Accordingly, we conclude that the Appellate Court was correct when it determined that the state failed to prove beyond a reasonable doubt that the defendant was not drug-dependent, and that the trial court’s instruction informing the jury that it might so find was improper.
II
The state alternatively argues that it does not bear the burden of proving beyond a reasonable doubt that the defendant was not drug-dependent. It claims that the defendant bears the burden of proving drug dependency by a preponderance of the evidence.10 We agree.
*608General Statutes § 21a-269 states: “In any complaint, information or indictment, and in any action or proceeding brought for the enforcement of any provision of this part, it shall not be necessary to negative any exception, excuse, proviso or exemption contained in said section, and the burden of proof of any such exception, excuse, proviso or exemption shall be upon the defendant.”* 11 We have held that the absence of drug dependency is not an element of the offense of sale of narcotics by a person who is not drug-dependent in violation of § 21a-278 (b). Rather, it is an exemption from liability under § 21a-269. State v. Januszewski, 182 Conn. 142, 166, 438 A.2d 679 (1980), cert. denied, 453 U.S. 922, 101 S. Ct. 3159, 69 L. Ed. 2d 1005 (1981). Therefore, it was not necessary for the state to negate drug dependency, but, rather, the defendant had the burden of proving that she was drug-dependent.
We have previously considered the meaning of “burden of proof” under § 21a-269. Id.; State v. Brown, 163 Conn. 52, 65-67, 301 A.2d 547 (1972). We stated that when a defendant offers “substantial evidence tending to prove his claim . . . [§ 21a-269] loses all operative effect.” State v. Brown, supra, 66-67. The state must then “prove beyond a reasonable doubt that the accused was not entitled to the benefit of any excuse, proviso or exemption claimed by him.” Id., 67; State v. Januszewski, supra, 169. In both of those cases, however, the defendant had offered no evidence at all to bring himself within the relevant exemptions.12 There*609fore, our discussions in those cases of the amount of evidence necessary for the defendant to meet his burden of proof was not essential to our decisions. Here, for the first time, we are presented with a case where the defendant has offered substantial evidence of drug dependency and we are squarely presented with the issue of the extent of the defendant’s burden of proof.13
Considering the plain language of the statute and confronting the results of an application of the law as stated m Brown and Januszewski, we conclude that the language of § 21a-269, which places the “burden of proof” on a defendant invoking the exemption specified by § 21a-278 (b), requires the defendant to carry the burden of persuading the jury by a preponderance of the evidence that he or she is drug-dependent. It would overly strain the language that places the “burden of proof” on a defendant to construe it merely to mean, as Brown and Januszewski suggest, that the defendant need only raise some evidence of his or her drug dependency to shift the burden to the state to prove a negative, i.e., lack of drug dependency, beyond a reasonable doubt.
Although the words “burden of proof” are occasionally construed to mean burden of production, that con*610struction is inappropriate in the present circumstances. To hold that the defendant bears only the burden of production would, in some instances, mandate that the defendant be acquitted of an offense under § 2 la-278 (b) based on the testimony of defense witnesses that was found to be entirely unpersuasive by the jury. That result is especially troubling in view of the difficulty of disproving drug dependency. As we recognized' in Januszewski, “[a] defendant’s drug dependency at the specific point of time in the past at which the offense occurred is certainly a matter . . . within his own knowledge. Moreover, the enactment of [§ 21a-269] appears to be an implicit recognition by the legislature of the difficulty created when any party is given the burden of proving the nonexistence of a certain fact, especially where, as in this case, the fact is the nonexistence of a physical status of the defendant at one, usually distant, point prior in time.” State v. Januszewski, supra, 167. Furthermore, in a case charging that the defendant is not drug-dependent, the state’s preparation of its case is hindered because it has no method by which to discover whether drug dependency will be an issue at trial. Compare Practice Book §§ 758 and 759 regarding the defense of mental disease or defect. We conclude that the legislature did not intend to mandate an acquittal whenever the defendant has offered evidence that might be completely disbelieved by the jury.14 Accordingly, we hold that § 21a-269 assigns to the defendant the burden of persuading the jury by a preponderance of the evidence *611that he or she is drug-dependent. See Dickerson v. State, 414 So. 2d 998 (Ala. App. 1982); State v. Buchman, 361 So. 2d 692 (Fla. 1978); Burgin v. State, 431 N.E.2d 864, 866-67 (Ind. App. 1982); State v. Carter, 214 Kan. 533, 521 P.2d 294 (1974); State v. Dixon, 546 S.W.2d 774 (Mo. App. 1977).
The defendant further asserts that even if we conclude that the legislature intended that the language placing the burden of proof on the defendant requires the defendant to prove by a preponderance of the evidence that he or she was drug-dependent at the time of the charged offenses, such a construction would place an unconstitutional burden upon the defendant. “ ‘[T]he Due Process Clause requires the prosecution to prove beyond a reasonable doubt all of the elements included in the definition of the offense of which the defendant is charged.’ ” (Emphasis in original.) McMillan v. Pennsylvania, 477 U.S. 79, 85, 106 S. Ct. 2411, 91 L. Ed. 2d 67 (1986); Patterson v. New York, 432 U.S. 197, 210, 97 S. Ct. 2319, 53 L. Ed. 2d 281 (1977). The federal due process clause does not bar state legislatures from placing the burden on a defendant to prove an affirmative defense or to prove that he or she falls within an exemption to liability for an offense. McMillan v. Pennsylvania, supra. We have concluded that the legislature intended drug dependency to be an exemption to liability under § 2 la-278, and not an element of that offense. State v. Januszewski, supra. Requiring the defendant to prove by a preponderance of the evidence that he or she falls within that exception does not relieve the state of its burden of proving beyond a reasonable doubt all of the elements of § 21a-278, and comports with federal due process.
Ill
Because we conclude that the state did not have the burden of proving beyond a reasonable doubt that the *612defendant was not drug-dependent, we disagree with the Appellate Court’s conclusion that the defendant is entitled to a judgment of acquittal. We conclude, rather, that the defendant is entitled to a new trial on the charge of sale of narcotics by a person who is not drug-dependent.
Relying upon our language in Brown and Januszewski, it was reasonable for counsel and the trial court to conclude that the defendant did not bear the burden of persuasion, and it is evident from the record that counsel and the court did draw that conclusion. Reasonably believing that she only needed to offer enough evidence to raise the issue of drug dependency, the defendant may not have introduced as much evidence as she would have had she understood that she had the burden of proving by a preponderance of the evidence that she was drug-dependent. Because we are stating for the first time that the defendant bears the burden of proving by a preponderance of the evidence that she was drug-dependent, and because the jury instructions relating to this issue did not reflect that burden, fairness requires that the defendant be afforded the opportunity to substantiate her claim. Therefore, we conclude that the defendant is entitled to a new trial on the charge of sale of a narcotic substance by a person who is not drug-dependent in violation of § 21a-278 (b). See Vines v. Orchard Hills, Inc., 181 Conn. 501, 514, 435 A.2d 1022 (1980).15
*613IV
The state next claims that the trial court’s instruction did not improperly allow the jury, rather than the court, to determine whether the issue of drug dependency had been raised. Having concluded that the defendant is entitled to a new trial, we need not address this issue because it is unlikely to recur on remand. State v. Williams, 202 Conn. 349, 365, 521 A.2d 150 (1987). Both parties agree that it is the function of the trial court to determine if the issue of drug dependency is raised, and our decision would turn upon a very fact specific review of the instant instruction. Since the instructions were improperly based upon the language of Brown and Januszewski, which we have now corrected, this issue should not arise again. In the future, the trial court should instruct the jury concerning the issue of drug dependency and the defendant’s burden of proof if it determines that there is “ ‘any foundation in the evidence, no matter how weak or incredible .. . .’ ” State v. Fuller, 199 Conn. 273, 278, 506 A.2d 556 (1986).
The judgment of the Appellate Court is reversed in part and the case is remanded to that court with direction that it be remanded to the trial court with direction to reverse the judgment with respect to the conviction of sale of a narcotic substance by a person who is not drug-dependent in violation of § 21a-278 (b), and to order a new trial on that charge.
*614In this opinion, Peters, C. J., Glass and Borden, Js., concurred.
General Statutes § 21a-278 provides in relevant part: “penalty for ILLEGAL MANUFACTURE, DISTRIBUTION, SALE, PRESCRIPTION OR ADMINISTRATION BY NON-DRUG-DEPENDENT PERSON ....
“(b) Any person who manufactures, distributes, sells, prescribes, dispenses, compounds, transports with the intent to sell or dispense, possesses with the intent to sell or dispense, offers, gives or administers to another person any narcotic substance, hallucinogenic substance other than marihuana, amphetamine-type substance, or one kilogram or more of a cannabis-type substance except as authorized in this chapter, and who is not at the time of such action a drug-dependent person, for a first offense shall be imprisoned not less than five years nor more than twenty years; and for each subsequent offense shall be imprisoned not less than ten years nor more than twenty-five years. The execution of the mandatory minimum sentence imposed by the provisions of this subsection shall not be suspended except the court may suspend the execution of such mandatory minimum sentence if at the time of the commission of the offense (1) such person was under the age of eighteen years or, (2) such person’s mental capacity was significantly impaired but not so impaired as to constitute a defense to prosecution.” This statute was formerly General Statutes § 19-480a.
General Statutes § 21a-277 provides in relevant part: “penalty for ILLEGAL MANUFACTURE, DISTRIBUTION, SALE, PRESCRIPTION, DISPENSING, (a) Any person who manufactures, distributes, sells, prescribes, dispenses, compounds, transports with the intent to sell or dispense, possesses with the intent to sell or dispense, offers, gives or administers to another person any controlled substance which is a hallucinogenic substance other than marihuana, or a narcotic substance, except as authorized in this chapter, for a first offense, shall be imprisoned not more than fifteen years and may be fined not more than fifty thousand dollars or be both fined and imprisoned; and for a second offense shall be imprisoned not more than thirty years and may be fined not more than one hundred thousand dollars, or be both fined and imprisoned; and for each subsequent offense, shall be imprisoned not more than thirty years and may be fined not more than two hundred fifty thousand dollars, or be both fined and imprisoned.”
General Statutes § 53a-48 provides: “conspiracy, renunciation, (a) A person is guilty of conspiracy when, with intent that conduct constituting a crime be performed, he agrees with one or more persons to engage in or cause the performance of such conduct, and any one of them commits an overt act in pursuance of such conspiracy.
“(b) It shall be a defense to a charge of conspiracy that the actor, after conspiring to commit a crime, thwarted the success of the conspiracy, under circumstances manifesting a complete and voluntary renunciation of his criminal purpose.”
General Statutes § 21a-279 provides in relevant part: “penalty for ILLEGAL POSSESSION. SUBSTITUTION OF MEDICAL TREATMENT FOR CRIMINAL sanctions, (a) Any person who possesses or has under his control any quantity of any narcotic substance, except as authorized in this chapter, for a first offense, may be imprisoned not more than seven years or be fined not more than fifty thousand dollars, or be both fined and imprisoned; and for a second offense, may be imprisoned not more than fifteen years or be fined not more than one hundred thousand dollars, or be both fined and imprisoned; and for any subsequent offense, may be imprisoned not more than twenty-five years or be fined not more than two hundred fifty thousand dollars, or be both fined and imprisoned.”
In certifying the third issue we asked whether the Appellate Court correctly ruled that the trial court’s instructions were improper because they required the jury to determine whether the defendant’s evidence was “credible.” The issue decided by the Appellate Court, however, was whether the jury was properly asked to determine whether the defendant’s evidence was substantial enough to raise the issue of drug dependency. Counsel for both parties have thoroughly briefed the issue decided by the Appellate Court. Accordingly, we will address the issue of whether the Appellate Court was correct in concluding that the trial court improperly instructed the jury to determine whether the defendant’s evidence was substantial, thereby raising the issue of drug dependency. Phillips v. Warden, 220 Conn. 112, 115-16 n.2, 595 A.2d 1356 (1991).
The defendant contends that the state’s claim that it elicited sufficient affirmative evidence through its cross-examination to prove beyond a reasonable doubt that she was not drug-dependent is not reviewable by this court. The defendant claims that the state failed to present this issue to the Appellate Court, and, therefore, asks that we conclude that certification was improvidently granted as to this issue. We conclude that the issue is properly reviewable. Following her conviction, the defendant appealed to the Appellate Court, claiming that the state had failed to meet its burden of proof. The state argued that it had met its burden of proof, stating at oral argument that facts were elicited on cross-examination which satisfied its burden of proof, and referred the Appellate Court to some of the facts set forth in its brief. The Appellate Court did not determine that the state’s claim was unreviewable, and, in fact, ruled on the issue, although disagreeing with the state’s contention that it had elicited such facts. State v. Hart, 23 Conn. App. 746, 755-56, 585 A.2d 103 (1991). Moreover, although the defendant filed an opposition to the state’s request for certification, she did not claim, as she could have pursuant to Practice Book § 4131, that this claim was unreviewable.
General Statutes § 21a-240 (18), in relevant part, defines drug dependence as “a state of physical or psychic dependence, or both, upon a controlled substance following administration of that controlled substance upon a repeated periodic or continuous basis . . . .”
General Statutes § 21a-240 (19), in relevant part, defines a drug-dependent person as “any person who has developed a state of psychic or physical dependence, or both, upon a controlled substance following administration of that substance upon a repeated periodic or continuous basis. ...”
The trial court instructed the jury that when drug dependency had become an issue in the case “the State is required to prove [it] beyond a reasonable doubt. Now, the State doesn’t have to introduce evidence on it, as it may have done in connection with other elements of this incident. To state all of the evidence in the case, there’s a pool of evidence for you to consider and any cross-examination done by the State of any witnesses who appeared on behalf of the defendant, in other words, Dr. Weiner. I believe evidence of non-drug dependency can be determined from the cross-examination, if you find that to be if the cross-examination has established in your mind beyond a reasonable doubt that the defendant was not drug-dependent. So all of that evidence is available to you to consider. It’s all of the evidence that was given to you in the case. And simply because the State has chosen to offer proof only by way of cross-examination, does not mean that they have not established non-drug dependency, if that be your conclusion. So the cross-examination is just as available as any other evidence that might come before you.” Further, the trial court instructed, “[Y]ou may find the State through cross-examination proved beyond a reasonable doubt that the defendant was not drug-dependent at the time of the incident.”
The state asserts that it elicited testimony on cross-examination susceptible to the following inferences: (1) The defendant was able to go for many hours on weekends without using drugs; (2) the defendant was not a “regular user” until after 1987; (3) Weiner testified that the Diagnostic and Statistical Manual III-R states that there is a list of criteria which constitutes the diagnosis of cocaine dependency; Hart did not satisfy the criteria; (4) Hart spent only $50 per week on cocaine; (5) the defendant always went to work promptly; (6) the defendant would remain at a bar for up to six hours without leaving and would not use drugs during that time; (7) the defendant’s ability to support herself was never affected; and (8) the defendant was never fired from a job because of cocaine use. Our review of the record does not support the state’s contention that all these facts can be fairly inferred.
Although the defendant asserts that the issue of who bears the burden of proof of drug dependency was decided by this court in State v. Brown, 163 Conn. 52, 301 A.2d 547 (1972), and State v. Januszewski, 182 Conn. 142, 438 A.2d 679 (1980), cert. denied, 453 U.S. 922, 101 S. Ct. 3159, 69 L. Ed. 2d 1005 (1981), and that the propriety of those decisions is not a properly certified question, we conclude that the definition of the state’s burden of proof is “inescapably intertwined” with the issue of whether the state met their burden. State v. Torrence, 196 Conn. 430, 434, 493 A.2d 865 (1985). Having determined that the issue was properly before us, fol*608lowing oral argument, we requested the parties to provide this court with simultaneous supplemental briefs limited to the following issue: “Once the defendant has raised the issue of drug dependency, does General Statutes § 21a-269 place the burden of proof on the state or on the defendant, and by what standard?”
Prior to 1983, this provision was found at General Statutes § 19-474. It has remained unaltered subsequent to its transfer.
In State v. Januszewski, 182 Conn. 142, 438 A.2d 679 (1980), the defendant claimed that the state had the burden of disproving his drug dependency, *609and in State v. Brown, 163 Conn. 52, 301 A.2d 547 (1972), the defendant claimed that the state had the burden of disproving that Ms possession of narcotics was licensed.
While we have not been squarely presented with the issue of the extent of the defendant’s burden of proof, the Appellate Court has. Consistent with our language in State v. Brown, 163 Conn. 52, 301 A.2d 547 (1972), and State v. Januszewski, 182 Conn. 142, 438 A.2d 679 (1980), the Appellate Court has affirmatively held that the defendant has the burden of raising the issue of drug dependency by offering evidence which, if credited by the jury, could raise a reasonable doubt as to whether she is not drug-dependent, and that if the issue is raised, the state must disprove beyond a reasonable doubt that the defendant is drug-dependent. State v. Rivera, 23 Conn. App. 592, 583 A.2d 931 (1990), cert. denied, 217 Conn. 807, 584 A.2d 1192 (1991); State v. McNeil, 21 Conn. App. 519, 574 A.2d 1314, cert. denied, 216 Conn. 807, 580 A.2d 64 (1990); State v. Luca, 19 Conn. App. 668, 563 A.2d 752 (1989).
The defendant refers this court to the legislative history of General Statutes § 21a-278, which was passed in 1971, and argues that comments made by legislators relating to that statute demonstrate that “burden of proof” as set forth in General Statutes § 21a-269 places only the burden of production upon the defendant. The defendant provided no legislative history of § 21a-269, which was passed in 1967. We do not find the comments made in 1971 concerning § 21a-278 to be particularly useful in determining the meaning of § 21a-269.
Relying upon the United States Supreme Court decision in Bouie v. Columbia, 378 U.S. 347, 84 S. Ct. 1697, 12 L. Ed. 2d 894 (1964), the defendant also claims that an application of this rule to her would violate principles of due process. We do not agree. In Bouie, the court stated: “[A]n unforeseeable judicial enlargement of a criminal statute, applied retroactively, operates precisely like an ex post facto law, such as Art. I, § 10, of the Constitution forbids. An ex post facto law has been defined as one ‘that makes an action done before the passing of the law, and which was innocent when done, criminal; and punishes such action,’ or ‘that aggravates a crime, or makes it greater than it was, when committed.’ Calder *613v. Bull, 3 Dall. 386, 390 [1 S. Ct. 172, 1 L. Ed. 648 (1798)].” Bouie v. Columbia, supra, 353. State courts are not allowed to effect an unforeseeable and retroactive judicial expansion of narrow and precise penal statutory language, since a court cannot do by statutory construction what the ex post facto clause prohibits a legislature from doing by legislation. Id., 352-54. This decision does not expand the offense of sale of narcotics by a person who is not drug-dependent in violation of General Statutes § 21a-278 (b). Because the elements of that offense remain unaltered, due process is not violated.