Opinion for the Court filed by Circuit Judge ROGERS.
On appeal from his sentence for distribution, and aiding and abetting the distribution, of cocaine base, appellant Yves Leandre principally contends that the district court erred by failing to reduce his sentence based upon his diminished mental capacity. Although the United States Sentencing Guidelines do not include an explicit reduction for “diminished mental capacity,” the policy statement contained in section 5K2.13 states that a court may reduce a sentence “to reflect the extent to which reduced mental capacity contributed to the commission of the offense.” U.S. SENTENCING GUIDELINES MANUAL § 5K2.13, p.s. (1997) [hereinafter “U.S.S.G.” or “Guidelines”]. The Sentencing Commission has thus - acknowledged that a defendant’s “diminished capacity” is a mitigating circumstance not adequately taken into account in formulating the Guidelines that would normally warrant a downward departure.
See
18 U.S.C. § 3553(b) (1988); U.S.S.G. § -5K2.0, p.s.;
Koon v. United States,
I.
Yves Leandre pleaded guilty to the unlawful distribution and aiding and abetting the distribution of five grams or more of cocaine base. 1 According to the presentenee report, Leandre was accountable for a total of 123.21 grams of crack cocaine; he had participated in three separate sales of a total of 115.21 grams of drugs to undercover officers and nearly 8 grams of cocaine base and related drug paraphernalia were found in his apartment. This placed him at a base offense level .of 32 under the Guidelines. See U.S.S.G. § 2Dl.l(c)(4). The district court, without objection by the government, reduced Leandre’s offense level to 29 because of his acceptance of responsibility for his criminal conduct. See U.S.S.G. § 3El.l(a), (b)(2). Leandre had also previously been convicted of two drug-related misdemeanors and a felony, for which he fell into criminal history category IV. See U.S.S.G. §§ 4A1.1, 4A1.2, 5A. The combination of these factors established a sentencing range of 121-151 months imprisonment. See U.S.S.G. § 5A. Prior to sentencing, Leandre sought to have his sentence reduced due to a variety of factors. 2 Of relevance here, he sought a downward departure from the Guidelines’ range because of his diminished mental capacity, noting in his memorandum in aid of sentencing his history of mental problems. He also requested departures based upon his responsibility to care for his two young children and the likelihood of his deportation ás a result of his conviction. The district court denied each request, but imposed the shortest term of incarceration within the applicable Guideline range: 121 months imprisonment followed by four years of supervised release.
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The scope of this court’s review of a district court’s decision not to depart from the Guidelines is limited but not insignificant. Because in deciding whether to depart “the district court must make a refined assessment of the many facts bearing on the outcome, informed by its vantage point and day-to-day experience in. criminal sentencing,” these courts have an “institutional advantage over appellate courts in making these sorts of determinations.”
Koon v. United States,
II.
The Guidelines do not expressly provide for a departure from the applicable sentencing range based on a defendant’s diminished mental capacity. Congress, however, has allowed district courts to depart from the Guidelines to reflect “mitigating circumstances of a kind, or to a degree, not adequately taken into consideration by the Sentencing Commission in formulating the [Guidelines.” 18 U.S.C. § 3553(b). In Chapter 5, Part K (Departures) of the Guidelines, the Sentencing Commission recognized certain factors that it had not taken fully into account, and listed in policy statements several encouraged or discouraged grounds for departures.
See
U.S.S.G. § 5K2.0, p.s.;
Koon,
at-,
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Leandre contends that the district court misconstrued the scope of its discretion to depart under section 5K2.13 by applying an overly-stringent standard for the fourth requirement. He maintains that the phrase “contributed to the commission. of the offense” encompasses a far broader meaning than the district court appreciated when it focused on the absence of any “direct connection between [Leandre’s] reduced mental capacity and the offense which was committed.” Noting that the Sentencing Commission’s policy statement only requires that a defendant’s mental incapacity contribute to the commission of a crime, Leandre contends that the district court improperly applied a “but-for” test in determining his eligibility for the departure. By applying such a heightened standard, Leandre maintains, the district court evaluated the grounds for the departure as if Leandre were asserting an insanity defense under 18 U.S.C. § 17
(1988).
In addition, Leandre contends, the district court failed to review the availability of the departure with a “view to lenity, as section 5K2.13 implicitly recommends” consistent with
United States v. Chatman,
The evidence before the district court at sentencing included a psychological report classifying' Leandre as mildly mentally retarded, with aii IQ of 66. The report, pro:-vided by Leandre, noted that he suffered from bouts of depression since early adolescence and has exhibited symptoms of “depressive psychosis.” Further, the report revealed, while incarcerated for a previous conviction, Leandre had attempted suicide after experiencing hallucinations and hearing demeaning voices that convinced him that he was a failure. At times, the report continued, these voices also expressed paranoid delusions. After his release from prison, the voices continued and, according to the psychologist, may have even intensified. Nevertheless, Leandre received no psychiatric treatment or medication after his release. Observing that throughout his life Leandre has repeatedly turned to drug use to cover over his depression and psychoses, the psychologist concluded that .Leandre’s addiction may have aggravated his conditions. Based upon this history, the psychologist further concluded that Leandre’s decision to sell drugs was “partly” influenced by his psychiatric difficulties. The psychologist opined that Leandre’s “ability to refrain from accepting the offer proposed to him was diminished by the recurrence of a serious depression with suicidal implications and the intensification of a psychotic Underlayer in' his psyche.”
The district court found, notwithstanding the psychologist’s causal conclusion, that Le-andre had failed to establish “the collection of factors” necessary for a downward departure under section 5K2.13. Of concern to Leandre on appeal, the court stated that “there must be a direct connection between the reduced mental capacity, and the offense which was committed.” Relying on
Sammoury,
The meaning properly ascribed to the term “reduced mental capacity” and its precise
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application in addressing a departure request involve areas that are not without difficulty. Little substantive guidance has been provided by the Sentencing Commission, either in the language of the Guidelines themselves or in the commentary or application notes.
See
U.S.S.G. § 5K2.13. Is the court to award a departure upon a showing of a nontrivial probability that the defendant’s diminished capacity increased the likelihood of the crime? Put otherwise, is the court to depart when presented with evidence that a defendant suffers from diminished mental capacity that possibly contributed, but was not essential, to the commission of the crime? Neither the Sentencing Commission nor the courts have given a clear answer. But similar concerns were traditionally considered by sentencing judges prior to the promulgation of the Guidelines in 'mitigation of the punishment of legally sane defendants suffering from various mental infirmities.
See generally
Norval Morris,
Madness and the Criminal Law
129-134, 142-44, 146-152 (1982); Henry Weihofen,
Mental Disorder as a Criminal Defense
209-10 (1954). This can be seen most clearly in the context of capital punishment where mental limitations and illnesses must be considered as mitigating factors when offered by the defendant.
See, e.g., Penry v. Lynaugh,
The mitigation of sentences to reflect a defendant’s reduced mental capacity is distinct from the conventional criminal law defense of “diminished capacity.”
6
In its most commonly accepted formulation, “diminished capacity” refers to situations where a defendant’s mental abnormality, although insufficient to exonerate the defendant on grounds of insanity, negates the element of
mens rea
required for conviction for the charged offense (i.e. an intent to kill, premeditation, etc.).
See United States v. Brawner,
*803
Against! this background it follows that the departure for “significantly reduced mental capacity” under section .5K2.13 does not require a showing of insanity.
Cf. United States v. Spedalieri,
Thus, as Leandre maintains, a defendant’s reduced mental capacity need not be the necessary cause of the commission of his crime in order for him to be eligible for a downward departure under section 5K2.13. In other words, a defendant is not required to prove that he would not have committed the offense but for the existence of his mental infirmity. All of the circuits to have addressed the issue of causation have rejected a “but-for” test. See,
e.g., United States v. Cantu,
Leandre’s comparison of two hypothetical defendants, however, suggests a subtler interpretation of the requirements for a departure under section 5K2.13. Under this interpretation, once the district court finds that a defendant was suffering from a reduced mental capacity at the time of the criminal conduct, the court has discretion to depart so long as the departure is roughly commensurate with the extent to which the diminished capacity affected the crime. “Courts need not measure contribution against a minimum threshold before allowing a departure^] [t]he proper focus is on matching the magnitude of the departure with the magnitude of the contribution.” Brown, supra, at 195. Presumably the magnitude would be zero if the district court found the contribution to be negligible, thus permitting no departure, but, *804 in-general, the court would be given a freer hand in departing from the Guidelines.
Other circuits examining the grounds for departures under section 5K2.13, have required an initial finding of causation before the district court can attempt to scale the punishment to the effects of the mental abnormality. For example, in
Frazier
the Seventh Circuit rejected the approach adopted by the sentencing judge who had assumed that there was a connection between the defendant’s mental disorder and the crime committed, requiring instead specific findings of causation before allowing a departure.
See Frazier,
In practice, this distinction may result more in a difference in emphasis than in any difference in substance. Whether a mentally infirm defendant whose reduced mental capacity did not contribute to his crime is
per se
ineligible for a departure, or is legally eligible but the extent of the departure must be nil, the result is the same. Under either view, the district court may not mitigate a sentence in the absence of some causal link. However, once some nexus is shown,
to any degree,
the district court may depart downwardly to reflect the extent of that contribution.
See Cantu,
Of course neither formulation clarifies what constitutes a “contribution” to an offense. Leandre’s interpretation seems to assume that any reduction in mental capacity will “contribute” to an offense in the sense that there will always be a nontrivial probability that the defendant’s mental capacity increased the likelihood of the crime. This contention is not directed at the relevant legal standard for a departure under section 5K2.13, however, but at the legitimacy of ever finding that there exists no causal connection between a defendant’s reduced mental capacity and his crime. Such an assumption would effectively negate the requirement of causation entirely, and therefore, given the language of section 5K2.13, we cannot credit it.
Cf. Frazier,
So understood, we conclude that the district court did not misapprehend its authority to depart from the Guidelines under section 5K2.13 by applying an overly stringent “but-for” test. The district court never considered the degree of causation necessary for a downward departure because it found that Leandre’s reduced mental capacity did not contribute to his crime in any way. Leandre’s reliance on the district court’s initial statement at sentencing that “there must be a direct connection between the reduced mental capacity and the offense which was committed” as proof of an inappropriate standard
8
is misplaced. The statement
*805
merely echoed the language of
Johnson,
where this court explained that a finding of a “direct connection” does not require the defendant’s reduced mental capacity to be the sole cause of his conduct.
See Johnson,
At the same time, when the district court conducts the factual inquiry required for an encouraged departure under section 5K2.13,
Chatman
makes clear that the court should proceed “with a view to lenity.”
Chatman,
The only remaining question is whether the district court’s causal finding was clearly erroneous. In finding that Leandre’s reduced mental capacity had not contributed to the offense, the district court considered the unsophisticated nature of the crime, the effect of Leandre’s voluntary drug use on his conduct, and his criminal history. Although reliance on some of these factors in isolation might be problematic, viewed together, they support the district court’s finding.
First, the nature of the offense. The district court properly emphasized the fact that “it really doesn’t require a great amount of intellectual sophistication to sell drugs or to understand that it is unlawful.” The mental, acumen required for the planning, preparation, and execution of a crime is a logical starting place for examining the effects of a defendant’s reduced capacity. While the particular mens rea required for conviction of the offense is not relevant to this assessment, the general level of intellectual sophistication associated with a crime is. Of course, the “intellectual sophistication of the crime” taken in isolation cannot be the end of the inquiry. Without suggesting that, the more complicated the criminal conduct, the more likely the mental incapacity contributed to it, it is nevertheless clear that even the simplest, most mindless. crime can be caused in part by a defendant’s mental incapacity. A defendant, for example, could be driven by a compulsive mental disorder to commit a crime unthinkingly. Section 5K2.13, therefore, is not limited to particular classes of crime and may be considered for any offense, no matter how unsophisticated.
The level of intellectual sophistication required for a crime is only relevant when considered in relation to the type of mental abnormality suffered by the. defendant. Here, the district court concluded that this factor belied any causal connection to the crime. The government’s proffer of evidence in support of Leandre’s plea showed that he was essentially a courier, bringing the drugs in response to instructions from a third person. There was evidence as well that Leandre participated in negotiations for the sale price of the drugs. Further, Leandre had been employed in the past, as both a plumber
*806
and a cook, despite his low IQ, depression, and other mental afflictions. Although the district court might well have reached a different conclusion,
see, e.g., Speight,
Second, voluntary drug use. The district court evaluated the effects of Leandre’s drug use on his mental capacity and his conduct. Clearly, the relationship between a defendant’s drug use and his conduct is relevant to an assessment of whether his reduced mental capacity was a cause of his offense. A departure under section 5K2.13 might remain available if a defendant’s drug use contributed only in part to a crime, because his mental infirmity may have also played a role. Because a defendant’s reduced mental capacity need not be the sole eause of the crime, both drug use and mental illness may contribute to the commission of an offense.
See Cantu,
In sentencing-Leandre, the district court’s evaluation of Leandre’s drug use was confined to stating that “the drug use may indeed have had an effect on his behavior and his state of mind.” The court did not indicate whether it had concluded that Leandre began to sell cocaine base in whole or in part because of his drug addiction. The psychologist’s report, on the other hand, indicated that Leandre began selling drugs to others as a result of his efforts to buy them for his own use. The district court apparently accepted the psychologist’s conclusion that Le-andre’s mental problems predated his drug use and were exacerbated by it. If the court had found that Leandre’s reduced mental capacity was actually caused by his voluntary drug use, Leandre would have been ineligible to receive a departure under section 5K2.13.
See Chatman,
Third, criminal history. In declining to grant a downward departure under section 5K2.13, the district court noted that Leandre had previously been convicted of attempted possession of POP (phencyclidine), possession of cocaine, and armed robbery. This was a proper consideration for the purpose of determining whether Leandre suffered from a “significantly reduced mental capacity” under section 5K2.13.
9
But it is unclear how a defendant’s past crimes would be relevant to determining whether his mental illness contributed to the criminal conduct for which he is to be sentenced. The government argued that Leandre had failed to show evidence that he was suffering from any psychosis at the time of the current offense. It is unclear which way this cuts. If a defendant has committed the same crime in the past or engaged in a particular pattern of behavior, and did not suffer from the same mental illness, then a sentencing court might reasonably conclude that the defendant’s current claim of reduced mental capacity did not contribute to the offense. Yet such an occurrence would probably be rare, and, in any event, is not Leandre’s case. In general, section 5K2.13 is an offense specific departure. The Guidelines contemplate other departures, and to the extent that section 5K2.13 is an encouraged departure,
see Koon,
at-,
Given the uncertainty about how a district court is to determine whether a defendant’s reduced mental capacity “contributed” to the commission of an offense, the district court cannot be faulted for exploring several alternative lines of analysis. Its consideration of the sophistication of Leandre’s offense and the effects of his voluntary drug use were proper factors to be evaluated and support the court’s ultimate conclusion that there was no causal nexus between Leandre’s offense and his mental disabilities. Although the psychologist concluded that Leandre’s decision to sell drugs was “influenced ... partly” by his “intellectual limitation and psychiatric illness,” the district court was not bound to accept that conclusion.
Cf. Sammoury,
Leandre belatedly contends, however, that the district court misconceived the nature of Leandre’s diminished capacity and the conditions that qualify as a “significantly reduced mental capacity” under section 5K2.13. In declining to depart under section 5K2.13, the court interpreted the departure as covering mental, psychological, and behavioral disorders that “diminish the defendant’s ability to reason.” The court doubted, however, that Leandre possessed a “mental deficiency that might not make apparent the relationship between cause and effect, crime and consequence.” Leandre contends that the district court underestimated its authority to depart by focusing exclusively on Lean-dre’s ability to reason, without considering any “volitional impairments” as suitable grounds for departure. He relies on
United States v. McBroom,
The district court's observation that "reduced mental capacity" refers to a defendant's ability to reason was taken directly from United States v. Edwards,
III.
Leandre’s other claims of sentencing error require only brief discussion.
His contention that the district cotirt eri~ed by failii~g to reduce his sentence due to his extraordinary famil~ circumstances under section 5H1.6 of the Guidelines is, given the limited scope of review of a denial of a departure request, fully met by United States v. Dyce,
Finally, Leandre’s contention that the district court erred by failing to reduce his sentence because of his status as an alien is meritless. A downward departure from the Guidelines “may be appropriate where the defendant’s status as a deportable alien is likely to cause a fortuitous increase in the severity of'his sentence.”'
United States v. Smith,
Accordingly, we affirm the denial of Lean-dre’s request for downward departures from the Guidelines and the judgment of conviction.
Notes
.
See
18 U.S.C. § 2(A) (1988); 21 U.S.C. § 841(a), (b)(l)(B)(iii) (1988). "Cocaine base” is more commonly known as “crack cocaine.”
See United States v. Edwards,
. In addition to the departures addressed in the instant appeal, Leandre asserted that he was entitled to a downward adjustment under U.S.S.G.. § 3B1.2 for his minor role in the drug offenses; under § 4A1.3 because the criminal history category overrepresents the seriousness of his prior crimes; under § 5K2.12 for coercion and duress; and, more generally, based on his "efforts to overcome [an] adverse environment," as well as a combination of all of these factors. Leandre does not challenge the denial of these departures on appeal.
. We have no occasion to decide whether after
Koon
our review of a denial of a departure is for abuse of discretion,
see Koon,
518 U.S. at- -,
. Section 5K2.13 provides:
If the defendant committed a non-violent offense while suffering from significantly reduced mental capacity not resulting from voluntary use of drugs or other intoxicants, a lower sentence may be warranted to reflect the extent to which reduced mental capacity contributed to the commission of the offense, provided that the defendant's criminal history does not indicate a need for incarceration to protect the public.
U.S.S.G. § 5K2.13, p.s.
. The government had argued first, that given the uncomplicated nature of the crimes, Leandre, who had previously worked as a plumber and a cook, was more than capable of understanding what was required of him and was sufficiently savvy to participate in negotiations for the amount of drugs he was to supply, and second, that while Leandre’s intellectual limitations may have made him more susceptible to .the lure of the drug trade, he had failed to show that his mental infirmities contributed to the commission of the offense in any "real sense.”
. The Sentencing Commission has included several conventional common law affirmative defenses as encouraged departures from the guide-' lines, such as coercion and duress, see U.S.S.G. § 5K2.12, and victim provocation, see U.S.S.G. § 5K2.10. These claims may not be sufficient to provide a full affirmative defense for acquittal, but they may be “morally salient under the guidelines.” Robert Weisberg, Guideline Sentencing, Traditional Defenses, and the Evolution of Substantive Criminal Law Doctrine, 7 Fed. Sentencing Rep. 168, 168 (1995); see also U.S.S.G. § 5K2.12 (acknowledging that judge may depart for coercion or duress "not amounting to a complete defense.”).
.
See
Joshua Dressier,
Understanding Criminal Law
§ 26.03 at 325 (1987) ("The partial-responsibility variant of the diminished capacity defense is not a defense to most crimes in the United States. In some states it is a defense to murder.”). For a general discussion of the confusion between "diminished capacity" and "diminished responsibility,” see Morse,
supra,
and Peter Ara-nella,
The Diminished Capacity and Diminished Responsibility Defenses: Two Children of a Doomed Marriage,
77 Colum. L.Rev. 827 (1977).
Compare also
Insanity Defense Reform Act of 1984, 18 U.S.C. § 17 (1988) (abolishing the affirmative defense of diminished responsibility in federal prosecutions),
with United States v. Chil
*803
dress,
. Leandre also contends that the district court’s conclusion that his mental deficiency did not affect his perception of "the relationship between cause and effect, crime and consequence” indicates that the court actually applied the test for an insanity defense. This statement, however, addresses the separate issue of whether the defendant possessed a "significantly reduced mental capacity,” not the extent to which any reduced capacity contributed to the crime. Furthermore, the phrase "cause and effect” cannot be equated with a determination that Leandre
*805
did not know "right from wrong” as would be required for a showing of insanity. Rather it is an evaluation of the defendant's ability to reason in accordance with
United States
v.
Edwards,
. Leandre’s criminal history would also be relevant to determining whether his incarceration was necessary to protect public safety, as an independent ground for denying him a departure under section 5K2.13. See U.S.S.G. § 5K2.13.
