dissenting:
Respondent, Clarence Stanback, a previously exemplary lawyer according to the evidence of record, admitted committing the serious disciplinary violations involved here. The hearing committee found that the medical evidence conclusively established that Stanback suffered from alcohol abuse and depression, the conditions to which he attributed his aberrant behavior and sought to prove in mitigation of sanction. See In re Kersey, 520 A.2d 321, 326 (D.C.1987). The *1120hearing committee also determined that Stanback met his burden of establishing both his disabling condition and causation as to all violations occurring “in or after March, 1991.”1 See In re Miller, 653 A.2d 201, 203 (D.C.1989). Consistent with the determination of the hearing committee and the recommendation of the Board on Professional Responsibility (Board), this court rejects Stanback’s mitigation claim, concluding that he failed to prove by clear and convincing evidence that his disabling condition also existed during the five months immediately preceding March 1991.2 However, the undisputed evidence, expert and otherwise, establishes that Stanbaek’s disability did not appear suddenly in March 1991, but as is typical of such conditions, evolved over a significant period of time, including the five-month period pivotal to his mitigation claim. The record shows that the factfinder made no credibility determinations against Stan-back and the other witnesses concerning the nature and duration of his disability; therefore, its rejection of his mitigation evidence during the critical period is not explicable on that basis. A review of the record will show that Stanback met the burden of proof to which he was held at the time of the proceedings before the Board, i.e., that his disabling condition “ ‘substantially affected’ the charged misconduct by a preponderance of the evidence.” Miller, 553 A.2d at 203. Whether tested against that standard or the clear and convincing evidence standard, which the court adopts today, the record demonstrates that Stanback established his disability and its connection with his misconduct. For these reasons and those which follow, I respectfully dissent from the opinion of the court.
Respondent’s Evidence of Disability
Respondent presented a compelling case in support of his mitigation defense. As the majority points out, the experts for both sides agreed “that respondent’s ability to conduct his professional activities was impaired by alcoholism by March 1991.” What the majority finds lacking, applying a clear and convincing evidence burden, is evidence of alcohol impairment at the earlier dates covering some of respondent’s violations of the disciplinary rules, specifically commencing from October 1990. Even applying the higher burden, however, the expert and lay witnesses, as well as the other evidence, make apparent that respondent’s alcoholism did not appear suddenly as a condition in March of 1991, but rather developed, as is the course of such conditions, over a significant period of time.
It should be noted at the outset that the hearing committee did not discredit the testimony of Stanback or any of the other seven witnesses who appeared on his behalf as to the nature and duration of his alcoholism and depression. The majority is mistaken in stating otherwise. See ante at 1116-1117. What the hearing committee rejected as warranting no weight was Stanback’s admitted speculation about when he misappropriated the funds. The hearing committee noted that Stanback “failed to introduce any evidence to show when he misappropriated the *1121funds” and, that he “merely speculated that the misappropriation occurred in March, 1991.” It was only on the issue of the timing of the misappropriation that the hearing committee accepted, as more reliable than Stanback’s admitted speculation, documentary evidence. It made no such finding as to the duration of Stanback’s disability. On the contrary, in concluding that Stanback’s condition “probably became disabling in March, 1991,” the hearing committee accepted the medical evidence, recognizing that much of it is based on “self-reporting.” The record reflects that the hearing committee made no credibility determinations against Stanback, the four doctors, two judges, and the other witness who testified concerning his condition. The question is whether the hearing committee’s finding as to the date of the disability “is supported by substantial evidence in the record, viewed as a whole.” See In re Micheel, 610 A.2d 231, 234 (D.C.1992) (citation omitted). Stanback argues, and an examination of the record will reveal, that it is not.
Dr. Ronald Wynne, an expert witness, provided the following testimony pertinent to the point:3
Basically, during his drinking and drugging years, which were roughly ’87 to ’91, Mr. Stanback clearly warranted a diagnosis of alcohol and probably cocaine dependence. That the combination of personality factors and stress factors sort of seemed to trigger off that excessive drinking. That there had been at least one period earlier in his life when he had had a similar kind of response to some stressors in his life. That he was certainly seriously disabled during that period of time_
He was alcohol and probably cocaine dependent for a period of probably four-plus years. And there was a period of probably a couple of years in the middle of that which seems to be when the events for which he was referred to the Bar took place, in which his alcohol and cocaine ingestion was such that, you know, he would be considered I think by any prudent professional to have been an alcoholic at that time....
So from the test data, from the information that he gave me, from the information that Suburban Hospital, Kolmac, and [Dr. Stanton] Samenow, all of which were consistent, I concluded that he was ingesting large amounts of alcohol at that time. And it had very serious consequences for his life.
Anybody drinking that much would have similar kinds of experiences.
Dr. Samenow also provided testimony bearing upon the issue of causation. He testified in pertinent part as follows:
Q: Dr. Samenow, do you have an opinion whether there was any relationship between Mr. Stanback’s alcohol usage and the ethical violations?
A: I do have such an opinion.
Q: And what is that?
A: My opinion is that there is a relationship because, as I indicated earlier, with the increasingly heavy drinking that he reported to me, and we are talking a lot of drinking_ But the intense use of alcohol and then later the cocaine, this was ’88, ’89° ’90, reaching its heaviest in ’91.
Indeed, all the experts testified that Stan-back was on a downward spiral beginning in the mid 1980’s. During cross examination, Dr. Wynne explained what that downward spiral actually meant:
Q: Is there any indication in the Suburban records where he indicates heavily drinking in ’88, ’89?
A: Well, you don’t do an intervention when you call in friends and a professional because somebody has just been drinking for a month. I think that what motivated his wife was that the drinking, which probably had been out of hand for a good while, really got out of hand.
Q: The intervention occurred at the end of 1991?
A: October ’91.
*1122Q: October ’91. Could his drinking have been out of hand, heavily out of hand, heavily drinking, drinking every night, using cocaine, for the previous six months?
A: Sure.
Q: And he could have been in the condition of October of ’91 whether he had been drinking heavily for the last six months or the last four years?
A: I hear you, but I don’t understand what you’re asking.
Q: You said they would not have done an intervention in October ’91 if he had only been drinking heavily for a month previous?
A: Yes.
Q: Could you have done an intervention in October ’91 and seen a man in the condition he was in October ’91 if he had been drinking heavily for the last six months?
A: Probably not.
Q: What if he had been drinking heavily for the last eight months?
A: I guess in my own — sort of theoretically, yes, I’ve never seen anybody who has had that short a period of time for whom someone has done an intervention. Usually these are patterns that go on for a number of years. There are people around him for whatever reason ignoring or kind of noticing it and kind of making excuses for the person. And finally something gets to a point, something is different for all kinds of people where they can no longer deny what they are seeing. The wife no longer can deny that, you know, there is a problem here.
In addition, Dr. George Kolodner, the medical director of the Kolmac Clinic where Stanback received treatment, listed the following “significant findings” on Stanback’s release form on July 8, 1992, which was an exhibit at the hearing:
The patient had a 5 year history of pathological use of alcohol. Manifestations of this included:
1. Reduced internal control over use
2. Abnormally high tolerance
3. Considerable time spent in use-related activities
4. Continued use despite adverse consequences (threatened with disbarment from the BAR)
The initial assessment was that the patient had a significant problem with alcohol, for which intensive treatment was indicated. The admitting diagnosis was Alcohol Dependence.
The facts underlying respondent’s violations of the disciplinary rules unquestionably cover a period from October 1990 through the fall of 1991.4 The testimony of the experts, some of which is above-described, as well as that of the lay witnesses, support respondent’s claim that he suffered from alcoholism during the relevant period. In addition to medical evidence of his alcoholism, respondent also presented evidence that his behavior during the period of his misconduct represented a radical departure from his pri- or behavior. We have recognized the significance of such evidence in determining whether alcoholism substantially affected a lawyer’s professional conduct. Miller, supra, 553 A.2d at 204.5
According to evidence stipulated to at the hearing, George Varoutses, a Virginia attorney, knew respondent through participation in the Arlington County Bar Association where both were past presidents. Varoutses had been impressed “with Stanback’s lawyer-ing skills” prior to the period associated with his disciplinary violations. However, Var-outses noticed that from about 1990 until March of 1992, respondent seemed to be *1123preoccupied, unhappy, and stopped attending bar functions. Not until March 1992 did Varoutses observe that Stanback “appeared to have made a complete behavioral turn around” and “became as involved and supportive of Bar Activities as he had been in the early years.”6
John Boyd, a Mend of Stanback’s for some twenty years, testified that from the period of October 1990 to December 1990, he noticed significant changes in Stanbaek’s behavior which led him to confront Stanback in December of 1990. Specifically, Boyd had observed an adverse change in the manner with which Stanback handled his practice. With respect to Stanback’s drinking habits during that period, Boyd testified as follows:
Q: Now, in that period of time, specifically, as best you can recall, what was he drinking? What kinds of drinks? We are talking about between approximately October and December of1990.
A: Jack Daniels and ginger ale would be — and then brandy. Jack Hennesy and ginger ale. To me those drinks don’t mix. If I drink — when I was drinking Jack Daniels, I drank Jack Daniels and water, Hen-nesy straight up, you know, but he always had to have something mixed with it. That is why I made the comment that he did not like the taste of liquor.
Q: Is this at a period when he was doing a lot of drinking?
A: Yes.
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Q: I understand you to have suggested during this period of time when you sat down and talked to him, or when you confronted him, at that point in time you had begun to believe that he might have an alcohol problem. Is that right — and I am not suggesting by asking this question that you are an expert in this, but I am just interested in you telling us what it is that made you believe, as clearly as you can, that he was having a problem with alcohol.
A: Okay. The reason I was coming — I came to that conclusion was because his whole behavior changed, was drastically different than what it had been in the past, and I was looking for reasons, and I think I always knew the reason, but I denied it, you know. I was in denial that he had a problem.
Boyd testified that his Mendship with Stan-back dissipated after the confrontation, but they have rekindled it since Stanback has been in recovery.
Judge William Newman, who went to law school with Stanback and shared office space with him from 1980-1988, described Stan-back as one of the “brightest and most hard working lawyers he knew.” He was “impressed” with Stanback’s ability to “juggle many responsibilities at the same time and consistently perform each thoroughly and well.” Judge Newman noted that Stanback had an active practice “and court appearance schedule for which he was always prepared and on time.” Judge Newman also stated that Stanback was active in the local and state bar associations.7
Judge Bruce Lee, who had known Stan-back as a professional colleague and Mend, described him as “a very effective lawyer who was prepared and who presented himself in court effectively on behalf of his clients.” He further testified that in 1990 some Mends made him aware that Stanback was missing court appearances and was not returning phone calls. He thought this was very unusual because “normally, if you called him, he would call you back.” Out of concern and a desire to discuss with Stanback the changes in his behavior, Judge Lee contacted him, and they agreed to meet; however, Stanback did not keep the appointment. Subsequently, they arranged to meet on October 28, 1990. Judge Lee expressed his *1124concerns to Stanback, and the two attempted to come np with ideas to help Stanback get things under control. Thereafter, they made several appointments with each other, but Stanback did not keep them. Judge Lee also testified that Stanback, who had been elected to a new position with the local bar, started to miss meetings almost immediately. His absence was so noticeable that some of the members asked Lee to discuss the possibility of resignation with Stanback. Finally, Judge Lee, who participated in the intervention to have Stanback address his alcoholism, testified that, while he had never been with Stan-back when he was drinking, he believed the changes in Stanback were related to the drinking because of what Stanback told him and his personal experiences with Stanback’s change in personality.
The foregoing examples of the other evidence presented at the hearing supports Stanback’s claim that his alcoholism and depression did not commence suddenly in March 1991, but occurred over time during a period which includes the earliest dates of the disciplinary violations in this case.8 Moreover, there was no evidence that Stan-back was not an alcoholic in the fall of 1990 and thereafter. The factfinder should not reject arbitrarily the uncontradicted testimony of an expert or lay witness absent a basis in the record for doing so. Pansing v. United States, 669 A.2d 1297, 1302 (D.C.1995) (citing Prost v. Greene, 652 A.2d 621, 629 (D.C.1995) and Rock Creek Plaza-Woodner Ltd. v. District of Columbia, 466 A.2d 857, 859 (D.C.1983)). The evidence, expert and otherwise, established that Stanback was suffering from alcoholism at the relevant time. Respondent clearly proved these facts even under the “clear and convincing” standard. On this record, the findings and conclusion of the hearing committee which the Board accepted, that there was no proof that Stan-back suffered from alcoholism between October 1990 and March 1, 1991, the time of the misconduct, is not supported by substantial evidence in the record, and this court should reject them. See In re Cooper, 591 A.2d 1292, 1294 (D.C.1991) (citations omitted).
Causation
Bar Counsel argues that even if respondent has proven his disability as of the relevant time period, he failed to prove by a preponderance of the evidence that the misappropriation was substantially affected by his disability. On the contrary, the evidence clearly met that burden. Dr. Samenow testified that respondent’s misconduct was related to his alcoholism. Dr. Wynne testified that respondent was seriously disabled at the relevant period and that it had serious consequences for his life. He also testified that it was his opinion that Stanback would not have misused his client’s funds absent his substance abuse. Even the expert witness called by Bar Counsel, Dr. Patterson, testified that respondent’s behavior was substantially affected by his disability. Dr. Patterson could not state the proposition in terms of a “but for” cause; however, when the question was framed in terms of whether the disability substantially affected respondent’s misconduct, an inquiry consistent with our opinions, the witness answered affirmatively. Respondent has shown a sufficient nexus between his misconduct and his alcoholism to meet his burden under Kersey, supra, 520 A.2d at 326-27; see also Cooper, supra, 591 A.2d at 1296; Miller, supra, 553 A.2d at 203. In light of the majority’s disposition of the case, I need not address the issue of respondent’s rehabilitation. See In re Temple, 596 A.2d 585, 591 (D.C.1991) (rehabilitation from disabling substance abuse is a significant factor in determining discipline).9
Burden of Proof
Our ease precedents hold that “where an attorney claims alcoholism as a mitigating circumstance in a disciplinary proceeding, *1125the attorney has the burden of proof on that issue and the attorney must show that alcoholism ‘substantially affected’ the charged misconduct by a preponderance of the evidence.” Miller, supra, 553 A.2d at 203 (emphasis added); accord, Temple, supra, 596 A.2d at 591. Today, the majority adopts a “three-pronged test” for establishing a Ker-sey 10 defense which elevates the burden of proof on issues pertinent to the establishment of that defense to one of clear and convincing evidence.11 In Miller, supra, this court considered and rejected specifically the higher burden of proof for this type of mitigation defense. Recognizing that there were other courts which had adopted a greater burden of proof and that the Board also adopted the higher standard in its Report and Recommendation in Kersey, supra, we rejected this standard. We then stated that
[njotwithstanding this, we believe that the preponderance of evidence standard is the more appropriate standard. As this court recognized in Kersey, difficult problems of proof are presented here. Given our view that the purpose of discipline in cases involving alcoholism should be to rehabilitate not punish, we think the lower standard is more appropriate.
Miller, supra, 553 A.2d at 203-04 n. 4; see also Kersey, supra, 520 A.2d at 326. While the majority restricts the “clear and convincing” evidence burden to proof that the attorney “suffered from an alcoholism-induced impairment at the time [of the misconduct],” that issue is central to proof of the requisite close nexus between the attorney’s misconduct and the alleged disability. See Temple, supra, 596 A.2d at 590. Therefore, the majority’s holding places upon the attorney the burden of proving that nexus by clear and convincing evidence contrary to our prior holdings. Proving the precise date of the onset of alcoholism and depression present the type of difficulties of proof which formed the basis for our rejecting the higher burden of proof in Miller, 553 A.2d at 203-04 n. 4. Although proof by clear and convincing evidence is a greater burden than our ease law required him to meet when he presented his ■ case, the record demonstrates that Stanbaek met this burden and established that he suffered from a disabling condition and that his professional conduct was substantially affected by it. See Kersey, 520 A.2d at 326. Therefore, I respectfully dissent.
. The Report and Recommendation of the hearing committee reads in this connection as follows:
The Committee concluded that Respondent was disabled only at the time of any violations occurring in or after March, 1991. As to any such charges, therefore, Respondent would be entitled to mitigation of sanctions if he could also demonstrate causation and rehabilitation.
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Because the weight of the evidence leads the Committee to find that the misappropriation of client funds occurred in or about October, 1990, he has failed to meet his burden as to causation on this charge. Similarly, there is no specific evidence of causation as to all other violations found to have occurred through the end of February, 1991. As to all misconduct occurring in or after March, 1991, the Committee concluded that Respondent has met his burden on the issue of causation.
. The hearing committee found that each of the violations, with one exception, occurred both before and after March 1991, but no earlier than October 1990. The exception involved conduct related to the violation of Rule 8.4(d) (interference with administration of justice), which occurred only after March 1991. As to the most serious charges, violations of DR 9-103 (A)(2) and Rule 1.15(a) (intentional misappropriation), the hearing committee found that Stanback failed to prove that "at the time of his misconduct in 1990, or in January-February, 1991, he was disabled by either alcohol dependence or depression.”
. Dr. Wynne had conducted over 3,000 evaluations of people who were substance dependent, over 300 evaluations of people who were substance abusers, had treated over 500 cocaine addicts, and between 150 and 200 alcohol addicts.
. The case proceeded on charges of violations of disciplinary rules in effect prior to January 1, 1991, and those in effect thereafter. The most serious of these violations included misappropriation in or about October 1990 as well as in January, February and March of 1991.
. In Miller, in assessing the attorney’s claim of mitigation, we noted:
Here, recognizing alcoholism's "severe effect on human behavior and psychology,” along with the record evidence of Miller's behavior (so foreign to that of her previous history of behavior), we would be blinking at reality to conclude that alcoholism did not “substantially affect” her professional conduct.
553 A.2d at 204.
. Rose Jackson, Stanback-’s secretary of five years, also provided insight into his earlier professional conduct. She described respondent as detail-oriented, cordial, and "extremely involved in all aspects of the practice."
. Judge Newman also stated that Stanback, who previously had managed his responsibilities thoroughly and well, became difficult to reach during the winter of 1991. He also recounted an embarrassing incident during that time where Stan-back consumed rapidly a large quantity of alcohol and behaved in a way that he had never seen before.
. Stanback’s depression was diagnosed by Dr. David George who described it as "situational adjustment reaction with depressed mood.” The majority points out that situational depression is a lesser form than clinical depression. In this case, however. Dr. George treated Stanback with the anti-depressant drug, Prozak.
. In light of my opinion that Stanback adequately established alcoholism as a mitigating factor, I would not reach his bias claim.
. See Kersey, supra, 520 A.2d at 326-27.
. See majority opinion at 1115-1116.