In re C.K., 391 P.3d 735

C.K., diagnosed with schizoaffective disorder (bipolar type), stopped participating in PACT and discontinued medication; family sought evaluation after escalating agitated/aggressive behavior.
At the ER, police and hospital staff observed aggressive, threatening conduct (including requests about a gun, lunging, spitting, and threatening gestures); C.K. was transferred to a therapeutic group home (Hays‑Morris).
Examining professional Kim Waples prepared a written evaluation summarizing her observations and third‑party reports (father, Sgt. Wilson, ER doctor, and Hays‑Morris records) and testified at the commitment hearing.
At hearing, Waples relied on her observations, the attached report, and Hays‑Morris records; over defense hearsay objection she repeated third‑party statements as bases for her opinion recommending involuntary commitment to Montana State Hospital under § 53‑21‑127, MCA.
The district court committed C.K. for 90 days; on appeal C.K. argued the court erred by admitting and considering inadmissible hearsay in Waples’s testimony.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether expert testimony that references or repeats out‑of‑court statements relied on by the expert is an improper admission of hearsay	C.K.: Waples impermissibly repeated hearsay and the court improperly considered it as substantive proof	State: Rule 703 allows experts to rely on and reference otherwise inadmissible information to explain the basis of their opinions; limitation under Rule 403 protects against prejudice	Court: Admission was proper under Rule 703 for the limited purpose of explaining the expert’s opinion and not as substantive proof; no abuse of discretion
Whether Rule 703 permits repeating the substance of out‑of‑court statements before the factfinder	C.K.: Perdue and Bailey prohibit an expert from repeating substance of inadmissible statements to the jury	State: Expert may reference such material if foundational requirements met and purpose is to show basis for opinion	Court: Clarifies Perdue and Bailey: experts may rely on and, with limitations, reference underlying hearsay under Rule 703, subject to Rule 403 restrictions

In re Mental Health of L.K.-S., 247 P.3d 1100 (Mont. 2011) (standard of review for involuntary commitment findings)
Perdue v. Gagnon Farms, Inc., 65 P.3d 570 (Mont. 2003) (expert reliance on third‑party statements treated as improper when offered as substantive proof)
Weber v. BNSF Ry. Co., 261 P.3d 984 (Mont. 2011) (Rule 703 admission may be excluded under Rule 403 for foundational or prejudicial concerns)
In re J.M., 704 P.2d 1037 (Mont. 1985) (examining professional may base opinion on hearsay in commitment proceedings under Rule 703)
State v. Bailey, 87 P.3d 1032 (Mont. 2004) (expert may rely on inadmissible evidence but should not disclose substance in a prejudicial manner)