Aubry v. State: Voluntary Intoxication May Be Considered With (But Not as the Sole Cause of) a “Disease or Defect of the Mind” for NGRI

1. Introduction

In AUBRY (MALCOLM) v. STATE (CRIMINAL), 142 Nev., Advance Opinion 14 (Feb. 26, 2026), the Supreme Court of Nevada reversed a jury conviction for first-degree murder of a victim 60 years of age or older and abuse of an older/vulnerable person resulting in substantial bodily or mental harm or death. The appellant, Malcolm Aubry, represented himself at trial and asserted, in tandem, legal insanity and self-defense.

The appeal centered on whether the jury received an instruction that incorrectly limited how it could evaluate an not-guilty-by-reason-of-insanity (NGRI) defense where the defendant’s alleged delusional state was attributed to a combination of a brain injury and cannabis intoxication. A secondary issue—addressed for guidance on remand—concerned whether the State violated NRS 174.234 by expanding expert cause-of-death testimony at trial beyond what was presented at the preliminary hearing without notice to the defense.

2. Summary of the Opinion

The court held that the district court committed reversible error by giving a voluntary intoxication instruction (jury instruction 17) that misstated Nevada insanity law. Specifically, the instruction told jurors they could not consider voluntary intoxication “in combination” with a mental disease or defect in evaluating insanity and suggested intoxication could not “contribute” to insanity. That conflicted with NRS 174.035(10)(a), which excludes only a disease or defect “caused solely by voluntary intoxication.”

The Supreme Court clarified a new, controlling rule: a jury may consider whether a combination of voluntary intoxication and a disease or defect of the mind resulted in insanity, but voluntary intoxication alone may not be the cause of the disease or defect of the mind. Because the improper instruction foreclosed the defense theory supported by expert testimony and the State repeated the instruction in closing, the State failed to prove the error harmless. The conviction was therefore reversed and remanded.

Separately, the court held it was error under NRS 174.234 for the State’s replacement medical examiner to expand potential causes of death (adding strangulation/asphyxia) beyond the preliminary hearing testimony (blunt force trauma) without proper disclosure, but the defendant did not show prejudice sufficient to establish plain error on that issue.

3. Analysis

3.1. Precedents Cited

  • Jackson v. State, 117 Nev. 116, 17 P.3d 998 (2001): Cited for the principle that the district court has broad discretion in settling jury instructions. Aubry did not dispute discretion in the abstract; he challenged whether instruction 17 was legally correct.
  • Newson v. State, 136 Nev. 181, 462 P.3d 246 (2020): Reinforced the standard of review—abuse of discretion/judicial error for the decision to give an instruction. The court nonetheless reviewed de novo the legal correctness of the instruction’s content.
  • Cortinas v. State, 124 Nev. 1013, 195 P.3d 315 (2008): Supplied the key framing rule: whether an instruction is a correct statement of law is reviewed de novo. This enabled the court to directly measure instruction 17 against NRS 174.035.
  • Kassa v. State, 137 Nev. 150, 485 P.3d 750 (2021): The district court relied on Kassa to justify limiting intoxication’s role in insanity. The Supreme Court distinguished Kassa: it addressed a different instruction, different arguments, and found no prejudice in context. Importantly, Kassa did not resolve the precise question presented here—whether intoxication may be considered with a disease/defect in an NGRI analysis under NRS 174.035(10)(a).
  • Love v. State, No. 52403, 2010 WL 3295682 (Nev. May 28, 2010) (Order of Affirmance): Distinguished because Love was reviewed for plain error, and the court there expressly did not decide whether the instruction was erroneous—only that any error was not plain. Aubry, by objecting, presented the issue cleanly for merits review.
  • Tavares v. State, 117 Nev. 725, 30 P.3d 1128 (2001): Provided the harmless-error framework for defective jury instructions. The court applied non-constitutional harmless error: reversal is required if the error had a “substantial effect” on the verdict.
  • Mathews v. State, 134 Nev. 512, 424 P.3d 634 (2018): Cited alongside Tavares to confirm the non-constitutional harmless-error standard used here.
  • Belcher v. State, 136 Nev. 261, 464 P.3d 1013 (2020): Established that the State bears the burden of proving harmlessness. That allocation mattered because the defense theory was plausibly viable under a correct instruction.
  • Newman v. State, 132 Nev. 340, 373 P.3d 855 (2016): Used to define plain-error review when a party fails to object at trial—relevant to the NRS 174.234 issue.
  • Moore v. State, 122 Nev. 27, 126 P.3d 508 (2006): Cited for the requirement that to affect substantial rights (and thus qualify as plain error), the error is usually required to be prejudicial. The defendant did not make an adequate prejudice showing on the disclosure issue.
  • Khoury v. Seastrand, 132 Nev. 520, 377 P.3d 81 (2016): Cited for waiver—arguments raised for the first time in a reply brief are deemed waived. This foreclosed a late-developed “trial by ambush” prejudice theory.

3.2. Legal Reasoning

(a) The statutory text controlled, and instruction 17 contradicted it

The court began with the governing statute. Under NRS 174.035(6), the defendant bears the burden of proving insanity by a preponderance. Under NRS 174.035(10)(a), a “disease or defect of the mind” does not include one “caused solely by voluntary intoxication.” The word “solely” is decisive: the statute excludes only intoxication-only mental conditions, not mixed-causation scenarios.

Yet jury instruction 17 told jurors they “may not consider” voluntary intoxication “in combination” with a mental disease or defect, and that the defendant must show the disease/defect “alone” prevented appreciation of the nature/wrongfulness of his acts—effectively rewriting “solely” into “at all.” The court therefore held instruction 17 was a material misstatement of Nevada law.

(b) The court expressly clarified the correct rule for future cases

The opinion does more than correct error; it clarifies doctrine: a jury may consider whether a combination of voluntary intoxication and a disease or defect of the mind resulted in insanity, but voluntary intoxication alone may not be the cause of the disease or defect of the mind.

This clarification harmonizes the NGRI framework with the statutory limitation. It preserves the legislature’s intent to bar “temporary insanity” theories rooted only in a defendant’s voluntary substance use, while still allowing defendants to prove that a qualifying disease/defect existed and that intoxication interacted with that condition in producing a legally significant delusional state.

(c) Harmlessness failed because the error directly disabled the defense theory and was reinforced by argument

Applying Tavares v. State and Mathews v. State, the court asked whether the error had a substantial effect on the verdict, with the State’s burden to prove harmlessness under Belcher v. State.

The record made the prejudice mechanism concrete: the defense neuropsychologist testified the delusional state was caused by the combination of traumatic brain injury and cannabis intoxication. Under a correct instruction, a jury could have found insanity. Instruction 17, however, told jurors they could not reach insanity if intoxication “contributed,” thus foreclosing the exact defense. The court further emphasized that the State repeated the erroneous instruction three times in closing, “exacerbat[ing] the issue.” The State therefore failed to show the verdict was not attributable to the error.

(d) The NRS 174.234 disclosure ruling: error without reversal

The court also addressed expert disclosure. NRS 174.234(2) requires timely notice of the subject matter and substance of expert testimony, and NRS 174.234(3) imposes a continuing duty to disclose additional required information.

Here, the original medical examiner testified at the preliminary hearing that death was caused by blunt force trauma, but at trial the replacement expert expanded the possible causes to include suffocation/strangulation/asphyxia, without a corresponding updated disclosure. The court held this violated the notice requirements of NRS 174.234.

Still, because there was no trial objection, review was for plain error under Newman v. State. The defendant did not demonstrate prejudice affecting substantial rights as required by Moore v. State, and a more developed “trial by ambush” theory was waived under Khoury v. Seastrand. Thus, the court did not reverse on this ground, but flagged the rule for guidance on remand.

3.3. Impact

  • Doctrinal clarity for NGRI cases involving substances: Trial courts may no longer instruct that voluntary intoxication cannot be considered “in combination” with a disease/defect. The correct line is “sole cause” versus “contributing factor alongside an independent disease/defect.”
  • Instruction drafting and litigation strategy: Prosecutors and defense counsel should scrutinize intoxication-related instructions for statutory conformity. Any instruction using “alone,” “did not contribute,” or categorical “may not consider in combination” language risks reversal when the defense theory is mixed-causation.
  • Closing argument constraints: Repetition of a legally erroneous instruction in closing can magnify prejudice and make harmlessness difficult to prove, as it did here.
  • Expert-disclosure compliance under NRS 174.234: If a replacement expert’s opinion differs materially from preliminary hearing testimony, the State must provide updated notice of the “substance of the testimony.” Even if not always reversible absent prejudice, the opinion signals heightened scrutiny of “expanded” expert theories introduced at trial.

4. Complex Concepts Simplified

Not guilty by reason of insanity (NGRI) under NRS 174.035
The defendant must prove that, because of a qualifying “disease or defect of the mind,” the defendant was in a delusional state and, due to that delusion, either did not understand the nature/capacity of the act or did not appreciate the act’s wrongfulness (i.e., not authorized by law).
“Caused solely by voluntary intoxication”
This statutory phrase means intoxication cannot be the only reason a defendant claims a mental disease/defect. But intoxication may still be part of the overall causal picture if there is another, independent disease/defect (e.g., a traumatic brain injury) that is not itself solely caused by intoxication.
Harmless error (non-constitutional)
Even if a court made a legal mistake, an appellate court will affirm if the State proves the error did not substantially affect the verdict. Here, the instruction likely mattered because it directly blocked the defense expert’s mixed-causation insanity theory.
Plain error
If a party did not object at trial, reversal generally requires (1) an obvious error and (2) prejudice affecting substantial rights. The court found an NRS 174.234 violation but no adequate showing of prejudice on this record.

5. Conclusion

Aubry establishes a clear rule for Nevada insanity litigation: juries may consider voluntary intoxication as part of an NGRI analysis when it operates alongside a qualifying disease or defect of the mind; the prohibition is only against diseases/defects caused solely by voluntary intoxication. By reversing on an instruction that erased this statutory distinction, the Supreme Court reinforced textual fidelity to NRS 174.035 and signaled that misstatements limiting a defense theory supported by evidence will rarely be harmless—especially when emphasized in closing.

The opinion also provides a cautionary procedural lesson under NRS 174.234: when the State’s expert cause-of-death theory materially expands from earlier proceedings, updated disclosure is required to avoid unfair surprise, even if reversal depends on a concrete prejudice showing.