Colorado § 16-8-109 - Testimony of lay witnesses.

Full text of Colorado Colorado Revised Statutes § 16-8-109 — Testimony of lay witnesses., with citation guidance and answers to common questions.

§ 16-8-109. Testimony of lay witnesses.

In any trial or hearing in which the defendant's mental condition is an issue, a witness not specially trained in psychiatry or psychology may testify as to the witness's observation of the defendant's actions and conduct, and as to conversations that the witness has had with the defendant bearing upon the defendant's mental condition, and the witness must be permitted to give opinions or conclusions concerning the defendant's mental condition.

Source: L. 72: R&RE, p. 229, § 1. C.R.S. 1963: § 39-8-109. L. 2025: Entire section amended, (HB 25-1058), ch. 15, p. 50, § 15, effective August 6.

ANNOTATION

Annotator's note. Since § 16-8-109 is similar to repealed § 39-8-1, C.R.S. 1963, and § 39-8-1, CRS 53, relevant cases construing those provisions have been included in the annotations to this section.

Nonexpert may not give hypothetical opinion of sanity. A nonexpert witness may never, in response to a purely hypothetical question stating the facts, be permitted to give an opinion on the question of sanity. Rupert v. People, 163 Colo. 219, 429 P.2d 276 (1967).

But a lay witness may, when a proper foundation is laid, express an opinion as to the sanity of another. People v. Median, 185 Colo. 101, 521 P.2d 1257 (1974).

Subject to the proper foundation, a psychiatric social worker may give opinion testimony on a defendant's mental condition. People v. Giles, 192 Colo. 240, 557 P.2d 408 (1976).

The foundation to be laid under this section must indicate that the conclusions of the witness bear directly upon the issue of sanity and not merely conclusions of fact as to conduct. People v. Medina, 185 Colo. 101, 521 P.2d 1257 (1974).

Requirements which must be met before a lay witness can express his opinion as to the sanity of another are: (1) It must be shown that the lay witness had an adequate means of becoming acquainted with the person whose sanity is in issue; and (2) the contacts must be proximate in time to the alleged offense. People v. Medina, 185 Colo. 101, 521 P.2d 1257 (1974).

Before opinion evidence from a nonexpert regarding the sanity of another can be admissible, the specific facts upon which the opinion is based must be first stated by the witness, and his testimony must also show a close or intimate relationship with the party alleged to be insane. People v. Medina, 185 Colo. 101, 521 P.2d 1257 (1974).

Before a lay witness is permitted to state an opinion regarding the sanity or insanity or mental competence or incompetence of a person whose mental condition is at issue, the witness must have had ample opportunity to observe the speech, manner, habits, or conduct of the person. People v. Medina, 185 Colo. 101, 521 P.2d 1257 (1974).

One who in the opinion of a trial court shows adequate means of becoming acquainted with a person whose mental condition is in issue, after detailing the facts and circumstances concerning his acquaintance and the acts and conversations upon which his conclusion is based, may give his opinion on the question of sanity. Leick v. People, 136 Colo. 535, 322 P.2d 674 (1958); Rupert v. People, 163 Colo. 219, 429 P.2d 276 (1967).

The opinion of a nonexpert is admissible only when it is made to appear that his acquaintance with a defendant, whose sanity is in issue, had the requisite nearness in time after the act charged, to persuade the court, in the exercise of a sound discretion, to receive it. Leick v. People, 136 Colo. 535, 322 P.2d 674 (1958).

The necessary predicate for lay opinion evidence is a showing of adequate means to have become acquainted with the person whose mental condition is at issue. People v. Giles, 192 Colo. 240, 557 P.2d 408 (1976).

A lay witness may give an opinion relative to the defendant's sanity if the witness details the facts which demonstrate his acquaintance with the defendant, and if those facts demonstrate that the acquaintance is close and that contacts were maintained at a point proximate in time to the alleged offense. People v. Osborn, 42 Colo. App. 376, 599 P.2d 937 (1979).

Discretion of trial judge. Trial judges have very broad discretion in determining whether or not any proffered witness is qualified to give opinion testimony. People v. Giles, 192 Colo. 240, 557 P.2d 408 (1976).

The testimony of a corrections officer who observed defendant during defendant's pre-trial incarceration had proper foundation. The record indicates that the witness testified concerning the witness's observations of defendant's behavior, not concerning the witness's opinion of defendant's mental condition. This testimony is specifically permitted by this section. People v. Henderson, 794 P.2d 1050 (Colo. App. 1990), rev'd on other grounds, 810 P.2d 1058 (Colo. 1991).

When discretion abused. Where foundation testimony fails to conform and where the proper guidelines are not adhered to in judging these requirements, it must be held that the trial court abused its discretion in permitting the admission of nonexpert opinion testimony. People v. Medina, 185 Colo. 101, 521 P.2d 1257 (1974).

Court abused its discretion in admitting some lay opinions from mental health providers who had not been properly noticed as experts by the prosecution. Some of the opinions were expert opinions improperly admitted under the guise of lay opinion testimony. The improper testimony related to symptoms of specific mental illness and opinions about whether defendant suffered from mental illness. The evidence relied upon the witness's specialized knowledge and training and, therefore, went beyond the bounds of lay opinion. The error in this case was harmless since there was ample evidence in addition to the improperly admitted opinions. Dunlap v. People, 173 P.3d 1054 (Colo. 2007).

The weight of a nonexpert's opinion is for the jury. Leick v. People, 136 Colo. 535, 322 P.2d 674 (1958); Rupert v. People, 163 Colo. 219, 429 P.2d 276 (1967).

Applied in People v. Johnson, 44 Colo. App. 118, 613 P.2d 902 (1980); People v. Wright, 648 P.2d 665 (Colo. 1982).

Source: official Colorado text · Last verified 2026-08-27

Frequently Asked Questions About Colorado § 16-8-109

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Section 16-8-109 ("Testimony of lay witnesses.") is part of the Colorado Revised Statutes, the codified statutory law of Colorado. It sets out the legal rule or procedure described in the text above. Statutes are amended regularly, so always verify against the official source.

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