Park Elliot Dietz (born August 13, 1948) is a forensic psychiatrist who has consulted or testified in many high-profile US criminal cases, including those of spousal killer Betty Broderick, mass murderer Jared Lee Loughner, filicide defendant Andrea Yates, and serial killers William Bonin, Jeffrey Dahmer, Ted Kaczynski, Richard Kuklinski, Joel Rifkin, and Arthur Shawcross.
He came to national prominence in 1982 during his five days of testimony as the prosecution's expert witness in the trial of John Hinckley Jr., who had attempted the assassination of President Reagan on March 30, 1981. Then an assistant professor of psychiatry at Harvard Medical School, Dietz testified that at the time of the shooting, Hinckley knew that his actions were wrong and had the capacity to control his behavior, and was therefore not legally insane. He now heads a forensic consulting firm, Park Dietz & Associates, and founded the world's first workplace violence prevention company, Threat Assessment Group, Inc.
Early life and education
Dietz was born on August 13, 1948, and raised in Camp Hill, Pennsylvania, a suburb of Harrisburg. His mother Marjorie Dietz had trained as a nurse and did hospital volunteer work, including activities at a local mental institution. His father Raymond Dietz was a physician, as was Dietz's grandfather.
Dietz graduated from Camp Hill High School in 1966 and that same year enrolled at Cornell University to major in Psychology and Biology. He was a member of Cornell's Theta Delta Chi fraternity. In 1970 he graduated with an A.B. cum laude in Psychology, and was a Phi Beta Kappa.
In 1970, Dietz received a senatorial scholarship to study at the University of Pittsburgh School of Medicine, transferring in 1972 to Johns Hopkins University. There, he was among a handful of students in the M.D.-Ph.D. Program in Behavioral Sciences funded by the National Institute of General Medical Sciences and the Grant Foundation of New York. From 1972 to 1975, while completing medical school and course requirements for a Ph.D. in Social Relations, Dietz also earned a Master of Public Health (MPH) degree.
Dietz worked with the school's noted public health professor Susan Baker on a study of drowning cases and their prevention and epidemiology, using the Haddon Matrix paradigm to categorize specific prevention measures for specific injuries. In 2012, Baker wrote that Dietz, "later applied the Matrix to the problem of rape, showing its value in formulating approaches to intentional injury ... and the Haddon Matrix probably played a role in his development of an entire industry addressed to workplace violence prevention."
Early career
After completing his residency in general psychiatry at Johns Hopkins in 1977 and fellowship in forensic psychiatry at the University of Pennsylvania in 1978, Dietz began teaching at Harvard Medical School, where at age 29 he was the school's youngest assistant professor. While teaching at Harvard, Dietz also was the director of forensic psychiatry at Bridgewater State Hospital, a facility for the criminally insane in Bridgewater, Massachusetts.
After four years at Harvard, Dietz became an associate professor at the University of Virginia in 1982, teaching law, behavioral medicine, and psychiatry at the UVA School of Law while also being the medical director at UVA's Institute of Law, Psychiatry and Public Policy. He taught on the Charlottesville campus for six years, and was promoted to Professor of Law in the School of Law and Professor of Behavioral Medicine and Psychiatry in the School of Medicine.
Significant contributions
Dr. Dietz has authored over 100 publications and consulted and/or testified in hundreds of criminal and civil cases. In addition to academic positions, Dr. Dietz has held hospital and administrative appointments; served on institutional committees, national public policy task forces, editorial boards for peer-reviewed scientific journals, and as a technical advisor for numerous TV series and films. In 2010, Dietz was awarded the "Seymour Pollack Award for Distinguished Contributions to Education in Forensic Psychiatry" by the American Academy of Psychiatry and the Law. In 2014, Biography.com listed Dr. Dietz among the 10 most famous psychiatrists in history. Dr. Dietz is a past President of the American Academy of Psychiatry and the Law, a Distinguished Life Fellow of the American Psychiatric Association, and a Fellow of the American Academy of Forensic Sciences. He is a forensic psychiatrist for both the FBI's Behavioral Analysis Unit and the New York State Police Forensic Sciences Unit. He was a member of the National Academy of Sciences Committee on Trauma Research, has conducted numerous studies of sex offenders, mentally disordered offenders, and violent criminals, directed a five-year study for the National Institute of Justice on mentally disordered offenders who threaten and stalk public figures, and headed a two-year privately funded study of risks to the children and families of executives and other public figures. Dietz's contributions to scholarship on sexual behavior and offenses include publications on sexual sadism, sexual masochism, sex offenses against children, exhibitionism, and sex offenses generally. Additionally, Dr. Dietz has authored many works on workplace violence, the stalking of high-profile individuals, and forensic psychiatry as a discipline.
John Hinckley Jr. trial
John Hinckley Jr. attempted to assassinate President Reagan outside Washington, D.C.'s Hilton Hotel on March 30, 1981, and Hinckley's 1982 trial included Dietz as an expert prosecution witness (while he still was teaching at Harvard). In his five days of testimony, Dietz told the jury that Hinckley told him that he felt shooting the president accomplished his goal of trying to impress actress Jodie Foster. Dietz quoted Hinckley as saying, Actually, I should feel good because I accomplished everything on a grand scale ... I did it for [Foster's] sake.
Assistant U.S. Attorney Roger Adelman, the chief prosecutor, argued that Hinckley may have been emotionally unstable at the time of the shooting, but that he was not so mentally disturbed that he could not understand what he did when he shot Reagan. Dietz and the colleagues whom he led wrote the prosecution's 628-page report on Hinckley's mental state.
Dietz diagnosed Hinckley with personality disorders: narcissistic, schizoid, and a mixed personality disorder with passive-aggressive and borderline traits, plus persistent sadness. Hinckley had, according to the Dietz-authored report, "a pattern of unstable relationships; an identity disturbance ... chronic feelings of emptiness and boredom ... inability to sustain consistent work behavior ... lack of self-confidence." But Dietz also told the jury that none of these personality issues free Hinckley from legal responsibility for shooting Reagan. "On March 30, 1981, Mr. Hinckley, as a result of mental disease or defect, did not lack substantial capacity to appreciate the wrongfulness of his conduct."
Dietz used Hinckley's assessment of the assassination location, as Reagan walked outside the Hilton Hotel, as an example of how Hinckley did "appreciate the wrongfulness" of his actions, but nonetheless went forward. Dietz said Hinckley had a, "long-standing interest in fame and assassination", and that he had studied, "the publicity associated with various crimes".
Hinckley's mental health state was clear enough that he knew the type of bullet that would do the most damage, Dietz told the jury, plus the step-by-step movements needed to get close to Reagan on March 30. "He was able to make other decisions on that date", Dietz said. "He decided where to go for breakfast, what to eat ... He made personal decisions of that sort. ... He deliberated and made a decision to survey the scene at the Hilton Hotel. There was no voice commanding him to do that ... He decided, as he tells us, to go to the Hilton to check out the scene to see how close he could get." He also explained that Hinckley summarized, "the situation as having poor security ... He saw that the range was close and within the distance with which he was accurate, and at the precise moment that he chose to draw his revolver there was a diversion of attention from him ... The Secret Service and others in the presidential entourage looked the other way just as he was pulling the gun ... Finally, his decision to fire, thinking that others had seen him ... indicates his awareness that others seeing him was significant because others recognized that what he was doing and about to do were wrong."
Hinckley's defense team argued that he was schizophrenic and thus not criminally responsible for his actions. After eight weeks of testimony, the jury on June 21, 1982, found Hinckley not guilty on all 13 counts by reason of insanity, a verdict that so shocked the nation that Senator Arlen Specter held a hearing of the Senate Judiciary Committee to question the jurors and both the American Psychiatric Association and American Bar Association appointed task forces to work on a revised test of insanity to clarify federal law.
The trial catapulted Dietz into the national spotlight: attorneys took special note of his unique knowledge of deviant behavior, with the FBI also seeking his expertise. His concurrent teaching at the University of Virginia from 1982 to 1988 ended with Dietz moving to Southern California to start his forensic consulting firm.
Threat Assessment Group, Inc. In 1987, Dietz founded Threat Assessment Group, Inc. (TAG), a Newport Beach, California-based consulting firm focused on preventing and managing workplace violence. The firm grew out of his earlier public health research into intentional injury prevention, including his application of the Haddon Matrix, an injury-prevention framework, to violence-related harm. Public health researcher Susan Baker has written that this line of work "probably played a role in his development of an entire industry addressed to workplace violence prevention."
TAG was among the first firms devoted specifically to workplace violence prevention, and in 1993 began offering formal training in the field. The company is credited with helping originate the cross-functional "Threat Assessment Team" model, in which human resources, security, legal, and mental health professionals jointly evaluate and manage behavioral risk within an organization. This approach has since been adopted more broadly in corporate security and human resources practice.
Dietz continues to serve as TAG's founder and president, overseeing case consultation work performed by a team that includes forensic psychiatrists, psychologists, and former FBI profilers. TAG operates alongside Dietz's earlier firm, Park Dietz & Associates, which provides related forensic and litigation consulting services.
Jeffrey Dahmer
Serial killer Jeffrey Dahmer murdered 17 boys and men from 1978 to 1991, all but one of them in Milwaukee, Wisconsin. Dietz was hired by the prosecution to evaluate Dahmer's claim that he was "guilty but insane". Dietz interviewed him for 18 hours, with the psychiatrist describing Dahmer as, "articulate, rational and motivated to speak the truth." During his two days of testimony, Dietz explained to the jury that Dahmer was not insane or driven to commit murder but, instead, had sexual disorders and exhibited sexually deviant behavior with his victims, but purposely drank himself to the point of intoxication when he killed. Dahmer, he said, also kept the skulls of 11 of his victims: far from being insane, Dietz said Dahmer, calmly and rationally, knew that keeping, "some of his favorite items, these keepsakes, [meant taking] a very big risk of being detected for all these serious crimes."