Trial Counsel Were Not Ineffective in Failing to Call a Psychiatrist at the Penalty Phase

Jesse Driskell. (

On June 1, 2021, the Missouri Supreme Court found that the circuit court did not err in finding that Jesse Driskell’s defense counsel were not ineffective. The trial counsel were not ineffective in failing to call an expert witness to testify, because counsel properly investigated a lack of capacity defense, consulted multiple qualified experts, utilized neuropsychological and genetic tests, and analyzed Driskill’s medical history of anxiety and depression.

Driskell perpetrated a home invasion, robbery, and double homicide shortly after using drugs. He was aiming to burglarize a couple’s shed, and when they found him he asked for money and, unsatisfied with the amount, raped the woman and killed both. He was sentenced to death twice over, in addition to receiving seven life sentences.

Driskell alleged there were errors made at both the guilt and penalty phases. Among the alleged penalty phase errors was the allegation that Driskell’s trial counsel were ineffective, because they failed to call an expert witness to testify at the penalty phase about Driskell’s mental health. Driskill argues that testimony of complex post-traumatic stress disorder (“PTSD”) resulting from childhood trauma and sexual abuse would have created a stronger defense as mitigating factors.

Driskell called multiple experts, including Dr. Robert Hanlon, a clinical neuropsychologist who testified that Driskell had been diagnosed with intermittent explosive disorder, bipolar disorder, and an anxiety disorder, suffered from panic attacks, and suffered abuse from his mother as a child. After testing, the neuropsychologist also found that Driskill had neurocognitive deficits, including executive dysfunction, memory disturbance, bipolar disorder, a history of multiple concussions, and chronic polysubstance abuse. Together, the experts suggested that the deficits made Driskill less able to control his behavior and impacted decision-making.

Dr. William Bernet, a professor emeritus of psychology specializing in the impact of genetics on criminal or violent behavior also testified after conducting a genetic test. He explained that Driskell’s childhood abuse, coupled with a low-activity version of a specific gene, makes it more likely an individual will be violent.

At the postconviction hearing, Dr. Stephen Peterson, a forensic psychiatrist, testified that Driskill’s complex PTSD and intermittent explosive disorder could have caused him to be under extreme mental or emotional disturbance at the time of the crime and substantially impaired his ability to understand the criminality of his conduct.

The trial counsel argued that they did not call a psychiatrist at the penalty phase because they presented evidence of Driskell’s mental health and history of abuse in other avenues. Trial counsel had made a strategic, intentional decision not to call every mental health expert who had prepared information for, or was consulted by, the defense, as those experts had harmful information or could not present relevant material.

The Court found that trial counsel engaged in due diligence, and their choices of witnesses to call was not unreasonable, so Driskill failed to overcome the strong presumption that trial counsel acted reasonably and rendered proper assistance. While the specific mental health problems might have differed, all experts reached the conclusion that these issues impacted Driskill’s behavior. The Court held that Driskill did not establish that the forensic psychiatrist’s testimony would have persuaded the jury to impose a life sentence, because of weaknesses in the psychiatrist’s testimony, its similarity to other penalty phase evidence, and the circuit court’s finding that the forensic psychiatrist was not credible. Therefore, the Court found that the circuit court did not clearly err in determining that trial counsel were not ineffective for failing to call a psychiatrist during the penalty phase.

Citation: Driskell v. State, 626 S.W.3d 212 (2021) (en banc).

Keywords: Missouri, death penalty, expert opinion testimony, adverse childhood experiences (ACEs), ineffective assistance of counsel, mitigating, aggravating, genetics

This post is the 107th post as part of an ongoing Center for Law, Brain & Behavior (CLBB) series tracking the latest developments in law and neuroscience cases. To see previous posts about recent cases, see the full case archive on the CLBB website. To see updates on legal scholarship, see the Neurolaw News, hosted by the MacArthur Foundation Research Network on Law and Neuroscience. This project is made possible through support of the Dana Foundation.



Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Center for Law, Brain & Behavior

Center for Law, Brain & Behavior

at Mass General Hospital, Harvard Medical School