--- title: "Psychology Expert Was Not Allowed to Opine on PTSD Symptoms" meta: "og:description": "The psychology expert was barred from testifying about the alleged mental abnormalities that the Defendant suffers from" "og:title": "Psychology Expert Was Not Allowed to Opine on PTSD Symptoms" author: "Expert Witness Profiler" description: "The psychology expert was barred from testifying about the alleged mental abnormalities that the Defendant suffers from" --- # Psychology Expert Was Not Allowed to Opine on PTSD Symptoms Posted on November 20, 2025 by Expert Witness Profiler Defendant Bryant Wilson (hereinafter “Defendant”) was charged with voluntary manslaughter and possession of contraband in prison, following a prison fight at USP Canaan that resulted in the stabbing death of Defendant’s victim on November 28, 2021. Defendant did not contest that the fight happened, nor that the death of his victim resulted; rather, he asserted that he acted in self-defense. On November 10, 2025, Defendant notified the Government that he wished to offer the expert testimony of Dr. [Stephen M. Timchack](https://expertwitnessprofiler.com/expert-witness/Stephen-Timchack/1569047), PsyD at trial, pursuant to [Rule 702](https://www.law.cornell.edu/rules/fre/rule_702#:~:text=Rule%20702%20sets%20forth%20the,is%20a%20relatively%20narrow%20inquiry.) of the Federal Rules of Evidence. He indicated that Timchak would testify to Defendant’s symptoms consistent with Post Traumatic Stress Disorder (“PTSD”). ## **Psychology Expert Witness** Dr. [Stephen M. Timchack](https://expertwitnessprofiler.com/expert-witness/Stephen-Timchack/1569047), PsyD has extensive training and background in both clinical and forensic psychology. Timchack has held faculty positions at Wilkes University, Misericordia University, and the University of Scranton. [Want to know more about the challenges Stephen Timchack has faced? Get the full details with our Challenge Study report](https://expertwitnessprofiler.com/order/add?eId=1569047&pId=3). ## **Discussion by the Court** Psychiatric evidence cannot serve as a defense unless it renders the Defendant legally insane, and even if the Defendant is deemed insane, such evidence is inadmissible unless it negates the _mens rea_ of the crime charged. Here, the Government thoroughly analyzed this issue with respect to the _mens rea_ requirement of voluntary manslaughter. Defendant did not dispute the Government’s argument; instead, Defendant narrowly focused on admissibility of the psychiatric evidence for purposes of his self-defense claim. Thus, Defendant essentially conceded that his PTSD evidence did not truly negate _mens rea_. The PTSD evidence did not negate mens rea, so it was inadmissible. Furthermore, Defendant’s analogous reasoning did not hold up under scrutiny. As the Government noted, “Battered woman’s syndrome focuses on the perceived threat posed by the batterer on the battered, while PTSD, as shown by Timchak’s report, focuses on a more general, perceptual perceived threat posed to the PTSD-sufferer by his surroundings . . . Here, [Defendant] was not under duress or defending himself against his “batterer” or someone who had assaulted him in the past. So [Defendant’s] PTSD is much less probative to the disputed issues here than those in the cases relied on by the Defendant.” Even if the Court were to find that PTSD negates the _mens rea_ of voluntary manslaughter in this case, the psychiatric evidence would still be inadmissible as both irrelevant and confusing to the jury. ## **Held** The Court granted the Government’s motion _in limine_ to preclude the expert testimony of Dr. Stephen Timchak. ## **Key Takeaway:** Simply, PTSD does not constitute insanity, nor does PTSD negate the _mens rea_ for voluntary manslaughter. The Court posits, as a theory, that PTSD could have inflamed Defendant’s reaction such that he carried out the killing in the heat of passion. In other words, PTSD likely offers an explanation, not a negation. ## **Case Details:** Please refer to the blog previously published about this case: [Prison Expert Was Not Allowed to Opine on Proper Staff Procedure](https://expertwitnessprofiler.com/prison-expert-was-not-allowed-to-opine-on-proper-staff-procedure) --- ## **You Might Also Like** ![Human Resources Expert Allowed to Opine on Termination](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-22T200052.311.jpg) [**Human Resources Expert Allowed to Opine on Termination**](https://expertwitnessprofiler.com/psychology-expert-was-not-allowed-to-opine-on-ptsd-symptoms/human-resources-expert-allowed-to-opine-on-termination)![Neuropsychology Expert Not Allowed to Opine on Cognitive Decline](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-22T144728.528.jpg) [**Neuropsychology Expert Not Allowed to Opine on Cognitive Decline **](https://expertwitnessprofiler.com/psychology-expert-was-not-allowed-to-opine-on-ptsd-symptoms/neuropsychology-expert-not-allowed-to-opine-on-cognitive-decline)![Human Factors Expert Not Allowed to Opine on the Tile](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-21T191749.960.jpg) [**Human Factors Expert Not Allowed to Opine on the Tile**](https://expertwitnessprofiler.com/psychology-expert-was-not-allowed-to-opine-on-ptsd-symptoms/human-factors-expert-not-allowed-to-opine-on-the-tile)![Insurance Expert Not Allowed to Opine on Legal Duties](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-21T155751.487.jpg) [**Insurance Expert Not Allowed to Opine on Legal Duties**](https://expertwitnessprofiler.com/psychology-expert-was-not-allowed-to-opine-on-ptsd-symptoms/insurance-expert-not-allowed-to-opine-on-legal-duties)![Law And Legal Expert Not Allowed to Opine on Contract Formation](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-20T213123.718.jpg) [**Law And Legal Expert Not Allowed to Opine on Contract Formation**](https://expertwitnessprofiler.com/psychology-expert-was-not-allowed-to-opine-on-ptsd-symptoms/law-and-legal-expert-not-allowed-to-opine-on-contract-formation)