C.R.S. § 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.