from the Superior Court in Pima County The Honorable Richard
D. Nichols, Judge No. CR20132518-001
of the Court of Appeals, Division Two 245 Ariz. 103');">245 Ariz. 103 (App.
Brnovich, Arizona Attorney General, O.H. Skinner, Solicitor
General, Joseph T. Maziarz, Chief Counsel, Criminal Appeals
Section, Michael T. O'Toole (argued), Assistant Attorney
General, Phoenix, Attorneys for State of Arizona.
L. Fullin, Pima County Legal Defender, Jeffrey Kautenburger
(argued), Assistant Legal Defender, Pima County Legal
Defender's Office, Tucson, Attorneys for Stephen Jay
J. Euchner, Tucson, Attorney for Amicus Curiae Arizona
Attorneys for Criminal Justice
JUSTICE TIMMER authored the opinion of the Court, in which
VICE CHIEF JUSTICE BRUTINEL and JUSTICES BOLICK, GOULD,
LOPEZ, and PELANDER (RETIRED) joined. CHIEF JUSTICE BALES
dissented in part and concurred in the judgment.
Although a defendant cannot use evidence of a mental disease
or defect to show he did not form a crime's requisite
mental state (mens rea), see State v. Mott, 187
Ariz. 536, 541 (1997); State v. Schantz, 98 Ariz.
200, 212-13 (1965), he may use evidence of a character trait
for impulsivity to cast doubt on the existence of
premeditation, see State v. Christensen, 129 Ariz.
32, 35 (1981), which forms part of the mens rea for first
degree murder under A.R.S. § 13-1105(A)(1), see
State v. Boyston, 231 Ariz. 539, 549 ¶ 50 (2013).
Here, we decide whether a defendant who introduces expert
evidence of a character trait for impulsivity to challenge
premeditation may also introduce evidence of brain damage to
corroborate the existence of that trait. We hold he cannot.
Stephen Jay Malone Jr. and A.S. lived together in a
tumultuous romantic relationship. On June 9, 2013, A.S. left
Malone, moving from their home with their three children. Two
evenings later, A.S., along with her sister, E.S., and two of
the children, drove to the home to return a gift to Malone.
On the way, A.S. spoke to Malone by phone and told him that
despite his threats, she was leaving him. When A.S. arrived,
Malone came up to the car, took the returned gift, and asked
her to stay so his mother, who was in the house, could see
the children. A.S. refused and drove away; Malone quickly
followed in another car. After a five-to-six-minute chase,
during which Malone blocked A.S.'s car twice, Malone
jumped from his car and fired multiple gunshots into
A.S.'s car, killing A.S. and injuring E.S.
The State indicted Malone on several charges, including
premeditated first degree murder, see §
13-1105(A)(1), the only charge at issue here. Before trial,
the State moved to preclude expert testimony from
psychologist James Sullivan, Ph.D, that Malone's
performance on neuropsychological assessment tests was
"consistent with significant and permanent diffuse brain
damage," meaning Malone was "more likely to have a
character trait for impulsivity." (Dr. Sullivan did not
obtain an MRI scan or like evidence to bolster his assessment
that Malone had brain damage.) While acknowledging that
Christensen permitted Dr. Sullivan to testify that
Malone had a character trait for impulsivity, the State
argued that Mott precluded evidence that brain
damage made the existence of this trait more likely. Over
defense objection, the trial court granted the motion and
precluded Dr. Sullivan from offering an opinion at trial
regarding brain damage.
At trial, Malone rebutted the State's allegation that he
premeditated A.S.'s murder by introducing evidence
suggesting he had acted impulsively. To that end, Dr.
Sullivan testified that, based on his observations and
psychological tests, Malone had a character trait for
impulsivity. Dr. Sullivan explained that people with this
character trait are compromised in their ability to think
through the consequences of their actions before acting,
although they are capable of doing so. The State did not
contest that Malone had a character trait for impulsivity but
nevertheless maintained he premeditated A.S.'s murder.
The jury agreed and found Malone guilty as charged.
In a split decision, the court of appeals concluded the trial
court erred by precluding Dr. Sullivan's testimony
concerning brain damage. State v. Malone, 245 Ariz.
103, 107 ¶ 16 (App. 2018). The court nevertheless found
the error harmless and therefore affirmed. Id. at
108-09 ¶ 22.
We granted Malone's petition for review (challenging
harmless error) and the State's cross-petition for review
(challenging error) because they involve a recurring issue of
statewide importance. We have jurisdiction pursuant to
article 6, section 5 of the Arizona Constitution.
We review the trial court's preclusion of Dr.
Sullivan's brain- damage testimony for an abuse of
discretion. See State v. Leteve, 237 Ariz. 516, 524
¶ 18 (2015). "An error of law committed in reaching
a discretionary conclusion may, however, constitute an abuse
of discretion." State v. Wall, 212 Ariz. 1, 3
¶ 12 (2006).
Before addressing the admissibility of Dr. Sullivan's
brain- damage testimony, we set forth general legal
principles underlying the issue. First, apart from insanity,
Arizona does not permit a defendant to introduce evidence of
a mental disease or defect as either an affirmative defense
or to negate the mens rea element of a crime. See
Mott, 187 Ariz. at 540-41; Schantz, 98 Ariz. at
212; see also A.R.S. § 13-502(A) ("A
person may be found guilty except insane if at the time of
the commission of the criminal act the person was afflicted
with a mental disease or defect of such severity that the
person did not know the criminal act was wrong."). Thus,
for example, in Mott this Court held that the trial
court properly excluded evidence that the defendant suffered
from battered-woman syndrome because it was offered to negate
the mens rea element for child abuse (knowledge or intent).
187 Ariz. at 539, 544-45. And in Schantz we held
that the trial court properly refused a jury instruction that
would have permitted the jury to consider expert evidence
that the defendant killed his wife "without his
deliberate volitional conscious awareness" to contest
the mens rea element for second degree murder (malice
aforethought). 98 Ariz. at 204-06, 213.
Using mental disease or defect evidence to refute the mens
rea element of a crime is commonly referred to as a
"diminished capacity" or "diminished
responsibility" defense. Mott, 187 Ariz. at
540; see Leteve, 237 Ariz. at 524 ¶
20. Such evidence does not provide a complete defense to a
crime or excuse it but "establish[es], by negating the
requisite intent for a higher degree of the offense, that in
fact a lesser degree of the offense was committed."
McCarthy v. State, 372 A.2d 180, 182 (Del.
1977) (quoting C.T. Drechsler, Annotation, Mental or
Emotional Condition as Diminishing Responsibility for