§ 16-8-103 — Pleading insanity as a defense

(1) (a) The defense of insanity may
only be raised by a specific plea entered at the time of arraignment; except that the
court, for good cause shown, may permit the plea to be entered at any time prior to
trial. The form of the plea is: Not guilty by reason of insanity; and it must be
pleaded orally either by the defendant or by the defendant's counsel. A defendant
who does not raise the defense as provided in this section is not permitted to rely
upon insanity as a defense to the crime charged but, when charged with a crime
requiring a specific intent as an element thereof, may introduce evidence of the
defendant's mental condition as bearing upon the defendant's capacity to form the
required specific intent. The plea of not guilty by reason of insanity includes the
plea of not guilty.

(b) This subsection (1) applies to offenses committed before July 1, 1995.

(1.5) (a) The defense of insanity may only be raised by a specific plea entered
at the time of arraignment; except that the court, for good cause shown, may permit
the plea to be entered at any time prior to trial. The form of the plea is: Not guilty
by reason of insanity; and it must be pleaded orally either by the defendant or by
the defendant's counsel. The plea of not guilty by reason of insanity includes the
plea of not guilty.

(b) This subsection (1.5) applies to offenses committed on or after July 1,
1995.

(2) If counsel for the defendant believes that a plea of not guilty by reason of
insanity should be entered on behalf of the defendant but the defendant refuses to
permit the entry of the plea, counsel may inform the court. The court shall then
conduct an investigation as it deems proper, which may include the appointment of
psychiatrists or forensic psychologists to assist in examining the defendant and
advising the court. After its investigation, the court shall conduct a hearing to
determine whether the plea should be entered. If the court finds that the entry of a
plea of not guilty by reason of insanity is necessary for a just determination of the
charge against the defendant, the court shall enter the plea on behalf of the
defendant, and the plea entered has the same effect as though it had been
voluntarily entered by the defendant.

(3) If a grand jury indictment or preliminary hearing has not been held prior
to the entry of the plea of not guilty by reason of insanity, the court shall hold a
preliminary hearing prior to the trial of the insanity issue. If probable cause is not
established, the case must be dismissed, but the court may order the district
attorney to institute civil proceedings pursuant to article 65 of title 27 if it appears
that the protection of the public or the accused requires a civil proceeding.

(4) Before accepting a plea of not guilty by reason of insanity, the court shall
advise the defendant of the effect and consequences of the plea.

Legislative History

Source: L. 72: R&RE, p. 226, � 1. C.R.S. 1963: � 39-8-103. L. 75: (3) amended, p. 926, � 26, effective July 1. L. 95: (1) amended and (1.5) added, p. 73, � 4, effective July 1. L. 2010: (3) amended, (SB 10-175), ch. 188, p. 783, � 21, effective April 29. L. 2013: (2) amended, (SB 13-116), ch. 115, p. 393, � 2, effective August 7. L. 2025: Entire section amended, (HB 25-1058), ch. 15, p. 40, � 4, effective August 6.