Last month, US District Court Judge W. Louis Sands rejected testimony from a neuropsychology expert witness in the criminal trial of Stewart Parnell, accused of defrauding customers of his now defunct Peanut Corporation of America (PCA) by selling them peanut products filled with harmful contaminants. Throughout 2008 and 2009, PCA distributed peanut products that led to a widespread outbreak of Salmonella that sickened 700 people and killed 9. Parnell, responsible for PCA quality control, hired Dr. Joseph Conley, Jr. to testify that his Attention Deficit Hyperactivity Disorder (ADHD) made it impossible for him to comprehend the problems leading up to the contamination – a unique, but ultimately unsuccessful approach.
Defendant Hires ADHD Expert Witness
Parnell is charged with fraud for knowingly selling peanuts with harmful microbiological content, and shipping a product that did not meet customer’s specifications. Central to the government’s case against him are several email correspondences between Parnell and other members of PCA which indicate that he was aware of the potential contamination and distributed the peanut products regardless. If the government can connect the contents of his emails to knowledge about the Salmonella contaminant, Parnell could be found guilty of intentionally defrauding customers by knowing the risks associated with distributing the tainted peanuts and withholding safety information.
In his defense, Parnell called upon Dr. Conley to testify that his ADHD prevented him from formulating the knowledge necessary to defraud because it left him incapable of understanding or appreciating the nature of the communications regarding the peanut contamination. Dr. Conley’s expert findings report that Parnell suffers from being restless, distracted, and inattentive – depriving him of the neurocognitive capacity to function in the role of quality control manager. According to Conley, “Mr. Parnell was and remains cognitively incapable of fielding, delineating, organizing, and integrating the daily plethora of phone calls and E-mails required in managing three companies.”
Dr. Conley explained that his expert witness testimony was not designed to defeat intent, but rather to demonstrate that Parnell did not, and could not, acquire the knowledge assigned to him in the indictment. Arguing that his ADHD made Parnell unlikely to create a scheme to defraud customers because he could not read or understand the necessary emails, Dr. Conley’s testimony represents a unique approach to the use of medical expert witnesses at criminal trials.
Judge Rejects ADHD Defense
In response to Dr. Conley’s ADHD testimony, the prosecution called Dr. David J. Schretlen to point out flaws in both his methodology and conclusions regarding the effect of Parnell’s alleged disorder. Dr. Schretlen testified that Parnell’s condition did not render him incapable of understanding emails because his responses to work communications demonstrated that he was able to comprehend the significance of the correspondence. Further, Parnell was not diagnosed with ADHD as a child, even though it is mostly commonly diagnosed in childhood, which called into question Dr. Conley’s research methods and diagnosis.
Citing a number of factors, including Dr. Schretlen’s expert analysis, Judge Sands rejected the use of Dr. Conley and his ADHD expert witness testimony. Pointing out that a defendant must “show a valid scientific connection” between testimony and the facts at issue in order have an expert witness admitted, Judge Sands found that Parnell had failed to forge the link between his alleged ADHD and the inability to understand the information regarding the contaminated peanuts. In Judge Sands’ opinion, Dr. Conley’s expert witness testimony designed to establish diminished capacity was not relevant because the case alleged Parnell formed a complex scheme to defraud customers, not that he had made errors in processing information contained in emails.
The case has gained attention for Parnell’s uncommon use of expert witness testimony to attempt an ADHD defense. Although ultimately unsuccessful because it was not relevant, the use of Dr. Conley to attempt a diminished capacity argument due to the neurocognitive deficiencies caused by ADHD is an interesting approach and one worth noting.
