Chauvin was accused of molesting two girls, aged fourteen and fifteen. In the State’s case in chief, it called a social worker to testify that she had given therapy to one of the girls and had diagnosed her to suffer from PTSD. The social worker testified that the girl’s PTSD symptoms were “consistent with” having been sexually abused.

In some child sex abuse cases, the defendant contends that the complaining child’s behavior suggests she has not been molested. In such cases, Louisiana courts and those of most other states will admit testimony that the child has PTSD and that her behavior is of the kind often shown by PTSD victims. The purpose of the PTSD evidence in such cases is not to prove the abuse directly, but to rebut the contention that the child’s behavior disproves it.

Chauvin’s lawyer, though, had not contended that the behavior of the girls was inconsistent with having been abused. The trial court admitted the PTSD evidence simply to prove that the girl in question had been molested. The supreme court noted that the courts of other states were divided on whether to admit PTSD evidence for that purpose. It listed Arizona, Hawaii, Maryland, Michigan, New Hampshire, and North Carolina as states that exclude the evidence, and New Mexico, Nevada, and Washington as states that admit it. (The court’s listing of Washington is questionable. In the case it cited, State v. Florczak, 76 Wn. App. 55, 882 P.2d 199 (1994), the court found that admitting testimony that a child’s PTSD was secondary to sexual abuse was error but harmless.)

The Louisiana court cited psychological literature showing that PTSD “is not designed to determine sexual abuse.” Rather, the court said, “PTSD assumes the presence of a stressor and then attaches a diagnosis to the child’s reactions to it.”