Conn. Gen. Stat. » Title 54 — CRIMINAL PROCEDURE · Chapter 961 — Trial and Proceedings after Conviction
Connecticut General Statutes

Conn. Gen. Stat. § 54-86i (2025)

Testimony of expert witness re mental state or condition of defendant

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No expert witness testifying with respect to the mental state or condition of a defendant in a criminal case may state an opinion or inference as to whether the defendant did or did not have the mental state or condition constituting an element of the crime charged or of a defense thereto, except that such expert witness may state his diagnosis of the mental state or condition of the defendant. The ultimate issue as to whether the defendant was criminally responsible for the crime charged is a matter for the trier of fact alone.

(P.A. 85-605.)

Cited. 207 C. 35; 209 C. 423; 210 C. 481; 216 C. 139; 224 C. 114; Id., 347; 225 C. 450; Id., 650.

Cited. 17 CA 257; 26 CA 94; 28 CA 425; 32 CA 170; 34 CA 629.

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Notes of Decisions
Cited in 10 cases (6 in the last 5 years), 1988–2024 · leading case: State v. Joyner, 625 A.2d 791 (Conn. 1993).
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State v. Joyner, 625 A.2d 791 (Conn. 1993). · cites it 4× “The basis of this claim is the court’s ruling to uphold the state’s objection to testimony by the defendant’s psychiatrist that the defendant’s history of mental disease or defect, schizoaffective disorder, alcoholism and drug abuse “substantially impaired his capacity to…”
State v. Vilalastra, 540 A.2d 42 (Conn. 1988). · cites it 2× “4 General Statutes § 54-86i; State v. Vilalastra, supra, 681 n.”
State v. Smith, 551 A.2d 742 (Conn. 1988). · cites it 4× “*427 He claims that the court acted contrary to this statutory provision in permitting the expert’s response and therefore committed plain error.”
State v. Bruny, 269 A.3d 38 (Conn. 2022). · cites it 2× “As for the defendant’s arguments concerning our abandonment of the ultimate issue rule in this narrow context, we disagree with the defendant that the rule change will result in testimony that invades the province of the jury.”
State v. Collins, 260 A.3d 507 (Conn. App. Ct. 2021). · cites it 2× “’’ Pursuant to General Statutes § 54-86i, ‘‘No expert witness testifying with respect to the mental state or condition of a defendant in a criminal case may state an opinion or inference as to whether the defendant did or did not have the mental state or condition constituting…”
State v. Miller, 327 A.3d 448 (Conn. App. Ct. 2024). · cites it 2× “‘‘In evaluating evidence, the [jury] is not required to accept as dispositive those inferences that are consistent with the defendant’s innocence.”
State v. Wright, 707 A.2d 295 (Conn. App. Ct. 1998). · cites it 2× “The court buttressed its determination that the admission of the testimony was improper by citing General Statutes § 54-86i. Id., 656-57. That statute provides that “[n]o expert witness testifying with respect to the mental state .”
State v. Gore, 269 A.3d 1 (Conn. 2022). · cites it 2× “For example, the rule we announce today would apply to any identifications of a defendant in cell phone videos or photographs.”
State v. Gore, 269 A.3d 1 (Conn. 2022). · cites it 2× “For example, the rule we announce today would apply to any identifications of a defendant in cell phone videos or photographs. 3 We emphasize that the rule change we announce today extends to identifications of any ‘‘person’’ depicted in surveillance video or photographic…”
State v. Gore, 269 A.3d 1 (Conn. 2022). · cites it 2× “For example, the rule we announce today would apply to any identifications of a defendant in cell phone videos or photographs.”
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