Deborah Denno was quoted in an Urban Milwaukee article about the importance of investigating evidence of childhood trauma in criminal cases.
Denno researched written court decisions reported in the online legal databases Westlaw and Lexis from 1992 to 2012. She found 800 criminal cases involving neuroscience evidence. She reviewed those and then narrowed her focus to the 266 cases involving childhood trauma.
Denno acknowledged that written opinions reported in Westlaw and Lexis are predominantly from appellate courts, so her research involved mostly appellate court decisions. Further, almost all of the 266 cases she reviewed in depth were homicide cases, and most involved the death penalty.
She looked particularly at the types of childhood trauma defendants had suffered, conditions caused by or related to the trauma, how evidence of the trauma or conditions was presented to courts, and the courts’ responses. From the 266 cases she identified 20 types of trauma, which she grouped as either family, developmental, or external trauma. On average, each defendant in the 266 cases had suffered five different types.
According to Denno, evidence of childhood trauma was predominantly introduced as a mitigating circumstance at sentencing; 246 of the 266 cases included such mitigation evidence. In 161 cases such evidence was introduced to support a claim of ineffective assistance of counsel. But in only 33 cases did defense counsel present childhood trauma or a resulting condition in defending against the crime. (Denno counted cases multiple times if the evidence was used in different ways.) Courts accepted at least some of the trauma evidence in 246 of the 266 cases.