## Facts

- The State prosecuted Ralph Alberico and, in a separate case, Richard Marquez for sexual offenses against minors; Alberico was also charged with kidnapping.
- At trial in Alberico’s case, the State offered testimony from Dr. Barbara Lenssen, a clinical psychologist.
- Lenssen evaluated the alleged victim and testified that the victim met diagnostic criteria for post-traumatic stress disorder (PTSD).
- Lenssen explained that PTSD is a psychological condition associated with traumatic events and described PTSD diagnostic criteria published by the American Psychiatric Association in the DSM-III-R.
- Lenssen testified that the alleged victim’s symptoms were consistent with those often seen in sexual-abuse victims and that the diagnosis was based on comparing reported symptoms to recognized criteria and clinical literature.
- The trial court admitted the PTSD testimony, and Alberico was convicted.
- In the consolidated appellate posture, the New Mexico Court of Appeals reversed the convictions, concluding the PTSD-related testimony was improperly admitted.
- The State sought certiorari, and the New Mexico Supreme Court agreed to review the admissibility of the PTSD testimony and, as a related matter, the general approach to scientific evidence under New Mexico law.

## Issues

1. Whether New Mexico should continue to require Frye “general acceptance” as a prerequisite for admitting scientific evidence, or instead apply the New Mexico Rules of Evidence, particularly Rule 11-702.
2. Whether a properly qualified mental-health professional may testify that an alleged victim of sexual abuse suffers from PTSD.
3. Whether such a professional may testify that the alleged victim’s symptoms are consistent with sexual abuse.
4. Whether PTSD testimony may be used to establish that sexual abuse in fact occurred, that the defendant caused the condition, or that the alleged victim is truthful.

## Decision

- The Supreme Court of New Mexico held that admissibility of scientific opinion testimony is governed by the New Mexico Rules of Evidence and that Frye’s “general acceptance” test is not a required threshold for admission.
- The Court held that, if the witness is properly qualified and the foundation is adequate under Rule 11-702 (and related rules), a mental-health professional may testify that an alleged sexual-abuse victim has PTSD.
- The Court held that the witness may also testify that the alleged victim’s symptoms are consistent with sexual abuse, when the testimony is sufficiently reliable and helpful to the jury.
- The Court held that the witness may not testify that sexual abuse actually occurred, that the symptoms were in fact caused by sexual abuse by the defendant, or that the alleged victim is telling the truth, because such statements improperly intrude on the jury’s credibility determinations.
- The Court rejected the Court of Appeals’ exclusionary approach and approved admission of properly limited PTSD testimony under the Rules of Evidence.

## Legal Principles

- Scientific and technical opinion testimony in New Mexico is admitted under the New Mexico Rules of Evidence, not under Frye as a mandatory gatekeeping formula.
- Rule 11-702 requires that the witness be qualified and that the opinion be based on knowledge that will assist the trier of fact; the trial court must assess reliability and fit.
- Rules 11-703 and 11-403 remain important: opinions must rest on permissible bases, and the court may exclude or limit testimony if unfair prejudice, confusion, or misleading effect substantially outweighs probative value.
- In sexual-abuse prosecutions, PTSD evidence may be admitted to explain a diagnosis and to describe symptom patterns consistent with sexual abuse, but it cannot be used as a proxy to prove the act occurred or to identify the perpetrator.
- An opinion that a complainant is truthful, or that the disorder proves the allegation, is improper because it amounts to credibility vouching and invades the jury’s role.

## Conclusion

New Mexico v. Alberico holds that New Mexico courts assess scientific opinion testimony under the New Mexico Rules of Evidence rather than Frye, and it allows qualified mental-health testimony diagnosing PTSD and describing symptoms consistent with sexual abuse, while barring opinions that sexual abuse occurred, that the defendant caused the condition, or that the complainant is truthful.


New Mexico v. Alberico, 116 N.M. 196, 861 P.2d 192 (1993)