Mont. Code Ann. » TITLE 46. CRIMINAL PROCEDURE · CHAPTER 14. MENTAL COMPETENCY OF ACCUSED · Part 1. Relevance of Mental Disease or Disorder
Montana Code Annotated

Mont. Code Ann. § 46-14-101 (2026)

Mental Disease Or Disorder -- Purpose -- Definition

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  1. MCA Contents
  2. TITLE 46
  3. CHAPTER 14
  4. Part 1
  5. 46-14-101 Mental disease or disorder -- purpose -- definition

TITLE 46. CRIMINAL PROCEDURE

CHAPTER 14. MENTAL COMPETENCY OF ACCUSED

Part 1. Relevance of Mental Disease or Disorder

Mental Disease Or Disorder -- Purpose -- Definition

46-14-101. Mental disease or disorder -- purpose -- definition. (1) The purpose of this section is to provide a legal standard of mental disease or disorder under which the information gained from examination of the defendant, pursuant to part 2 of this chapter, regarding a defendant's mental condition is applied. The court shall apply this standard:

(a) in any determination regarding:

(i) a defendant's fitness to proceed and stand trial;

(ii) whether the defendant had, at the time that the offense was committed, a particular state of mind that is an essential element of the offense; and

(b) at sentencing when a defendant has been convicted on a verdict of guilty or a plea of guilty or nolo contendere and claims that at the time of commission of the offense for which the defendant was convicted, the defendant was unable to appreciate the criminality of the defendant's behavior or to conform the defendant's behavior to the requirements of the law.

(2) (a) As used in this chapter, "mental disease or disorder" means an organic, mental, or emotional disorder that is manifested by a substantial disturbance in behavior, feeling, thinking, or judgment to such an extent that the person requires care, treatment, and rehabilitation.

(b) The term "mental disease or disorder" does not include but may co-occur with one or more of the following:

(i) an abnormality manifested only by repeated criminal or other antisocial behavior;

(ii) a developmental disability, as defined in 53-20-102;

(iii) drug or alcohol intoxication; or

(iv) drug or alcohol addiction.

History: En. 95-501 by Sec. 1, Ch. 196, L. 1967; amd. Sec. 3, Ch. 184, L. 1977; R.C.M. 1947, 95-501; amd. Sec. 1, Ch. 713, L. 1979; amd. Sec. 149, Ch. 800, L. 1991; amd. Sec. 199, Ch. 42, L. 1997; amd. Sec. 1, Ch. 595, L. 2003; amd. Sec. 4, Ch. 209, L. 2013; amd. Sec. 10, Ch. 161, L. 2015.

Notes of Decisions
Cited in 28 cases (12 in the last 5 years), 1979–2026 · leading case: State v. Watson, 686 P.2d 879 (Mont. 1984).
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State v. Watson, 686 P.2d 879 (Mont. 1984). · cites it 34× “III Did the court err in instructing the jury on the law of mental disease or defect? Defendant contends that section 46-14-101, MCA creates a conclusive presumption, the effect of which was to tell the jury that they should accept as true, without proof, that a mental disease…”
State v. Korell, 690 P.2d 992 (Mont. 1984). · cites it 18× “See section 46-14-101, MCA. Watson had entered two Missoula apartments, stabbed a sleeping woman thirty-five times and also stabbed a man who came to her rescue.”
State v. Wooster, 1999 MT 22, 974 P.2d 640. · cites it 40× “” Wooster argues that the District Court and several mental health professionals have concluded that he has an antisocial personality disorder but that § 46-14-101, MCA, specifically excludes antisocial personality disorder from consideration as a mental disease or defect.”
State v. Wooster, 2001 MT 4, 16 P.3d 409. · cites it 10× “” Concluding that he would pose an unreasonable threat to himself or others if released, the District Court denied Wooster’s petition for release.”
Sandstrom v. Montana, 442 U.S. 510 (1979). · cites it 2× “" [2] Petitioner initially filed a notice of intent to rely on "mental disease or defect excluding criminal responsibility" as a defense.”
State v. Olson, 593 P.2d 724 (Mont. 1979). · cites it 15× “1947, now section 46-14-101 MCA; Powell v. Florida (5th Cir.”
State v. S. Pelletier, 2020 MT 249, 473 P.3d 991. · cites it 3× “Defense counsel presented the evidence of the mental disease or disorder as a mitigating sentencing consideration pursuant to §§ 46-14-101(1)(b), -311, and -312, MCA. The District Court ultimately sentenced Pelletier to serve 40 years in the Montana State Prison, with 20…”
State v. Pittman, 2005 MT 70, 109 P.3d 237. · cites it 3× “*332 ISSUE 6 ¶38 Did the District Court abuse its discretion in sentencing Pittman to prison instead of to the custody of the Department of Public Health and Human Services? ¶39 Section 46-14-101, MCA, requires the sentencing court to consider a defendant’s mental disease or…”
State v. Woods, 945 P.2d 918 (Mont. 1997). · cites it 10× “Section 46-14-101, MCA. Application for discharge or release may be made by the director of the institution to which the person was committed, the director of the Department of Public Health and Human Services, or the person committed.”
State v. Mercer, 625 P.2d 44 (Mont. 1981). · cites it 3× “In 1979, the legislature amended section 46-14-101, MCA, by eliminating the definition of mental disease or defect, excluding responsibility.”
Estates of Louisa & Swen Swanson, 2008 MT 224, 187 P.3d 631. · cites it 4× “14 was capable of forming the requisite intent, the District Court must take into account the evidence concerning Jeanette’s mental condition, as required by § 46-14-101(1), MCA. CONCLUSION ¶35 In sum, we hold that the District Court erred by concluding, as a matter of law, that…”
State v. Hess, 828 P.2d 382 (Mont. 1992). · cites it 2× “Clara further argues that statutes governing the procedure for mental evaluation when mental state is an issue, §§ 46-14-101 to -313, MCA (1989), are inapplicable here because the defense of justifiable use of force based on battered woman syndrome does not place a defendant’s…”
Show all 28 citing cases →
Mont. Code Ann. § 46-14-101(1): 4 cases
Estates of Louisa & Swen Swanson, 2008 MT 224, 187 P.3d 631. “14 was capable of forming the requisite intent, the District Court must take into account the evidence concerning Jeanette’s mental condition, as required by § 46-14-101(1), MCA. CONCLUSION ¶35 In sum, we hold that the District Court erred by concluding, as a matter of law, that…”
State v. Dawson, 2006 MT 69, 133 P.3d 236.
State v. C. Kepler, 2024 MT 173, 554 P.3d 138.
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
Mont. Code Ann. § 46-14-101(1)(a)(i): 2 cases
S. Hanway v. K. Fouts, No. OP 21-0503 (Mont. Nov. 2, 2021).
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
Mont. Code Ann. § 46-14-101(1)(a)(ii): 3 cases
State v. Logue, 2021 MT 22N, 479 P.3d 527.
State v. A. Smith, 2025 MT 281, 580 P.3d 708.
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
Mont. Code Ann. § 46-14-101(1)(b): 2 cases
State v. S. Pelletier, 2020 MT 249, 473 P.3d 991. “Defense counsel presented the evidence of the mental disease or disorder as a mitigating sentencing consideration pursuant to §§ 46-14-101(1)(b), -311, and -312, MCA. The District Court ultimately sentenced Pelletier to serve 40 years in the Montana State Prison, with 20…”
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
Mont. Code Ann. § 46-14-101(2): 5 cases
State v. S. Pelletier, 2020 MT 249, 473 P.3d 991. “Defense counsel presented the evidence of the mental disease or disorder as a mitigating sentencing consideration pursuant to §§ 46-14-101(1)(b), -311, and -312, MCA. The District Court ultimately sentenced Pelletier to serve 40 years in the Montana State Prison, with 20…”
State v. Olson, 593 P.2d 724 (Mont. 1979). “1947, now section 46-14-101 MCA; Powell v. Florida (5th Cir.”
State v. Meckler, 2008 MT 277, 190 P.3d 1104.
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
State v. Arnold, 2015 MT 163N.
Mont. Code Ann. § 46-14-101(2)(a): 4 cases
State v. R. McCauley, 2021 MT 181N, 490 P.3d 1260.
Warner v. State of Montana, No. 9:19-cv-00103 (D. Mont. Oct. 31, 2022).
S. Hanway v. K. Fouts, No. OP 21-0503 (Mont. Nov. 2, 2021).
State Farm Fire & Cas. Co. v. Hansen, No. 1:20-cv-00064 (D. Mont. Mar. 21, 2022).
Mont. Code Ann. § 46-14-101(2)(b)(ii): 1 case
State v. Myers Starks, 2026 MT 93, 588 P.3d 1243.
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