Mark Hallett, MD, Leader in Study of Functional Neurological Disorders, On Future Challenges of the Field
By Dan Hurley
January 19, 2023
Article In Brief
After a storied career that saw him rise to the role of chief of the human motor control section of the National Institute of Neurological Disorders and Stroke, 79-year-old Dr. Mark Hallett enters retirement and reflects on his life's work.
In the 19th century, Jean-Martin Charcot called it “hysteria.” Then Sigmund Freud, early in the 20th century, called it “conversion disorder.” And then came Mark Hallett, MD, FAAN, who in the 21st century has played a key role in redefining and revolutionizing our understanding of what is now called functional movement disorder, which is included in the broader illness called functional neurological disorder (FND).
On Dec. 12, scientists from around the world met on the National Institutes of Health (NIH) campus to celebrate the extraordinary career of Dr. Hallett, who served for decades as chief of the human motor control section of the National Institute of Neurological Disorders and Stroke (NINDS).
In an interview with Neurology Today, Dr. Hallett said what the field needs most now is not another clinical trial or preclinical experiment (although they certainly would be welcome).
“The most important challenge is education,” he told Neurology Today in an hour-long interview. “There are a lot of things we know at the moment, but that information is not well disseminated. Ignorance is a big problem.”
Second most necessary, he said, is greater availability of treatment programs.
“Treatment in the United States and around the world by people who are well trained is very limited,” Dr. Hallett said. “Very often, we make the diagnosis here but we can't find anybody willing to treat. It's terrible. If the patients are untreated, they are not going to do well. Studies show if you treat with currently accepted methods, you can benefit about 75 percent of patients.”
Current challenges notwithstanding, the field is far ahead from where it stood when Dr. Hallett opened a movement disorders clinic at NINDS in the mid-1980s.
“We were making the diagnosis of what was then called psychogenic movement disorders in 30 percent of the patients coming to the clinic,” he recalled. “I began to think about the situation and realized that this was a big problem. First of all, it wasn't a rare disease. But doctors were having trouble with the diagnosis, which is why we were seeing so many of them. And there was no research going on. Neurologists and psychiatrists were not very interested in the problem. We didn't have good treatments, and the prognosis was terrible.”
That led him, in 2006, to publish an editorial, “Psychogenic Movement Disorders: A Crisis for Neurology.” Since then, Dr. Hallett and other researchers have shown in dozens of papers that movement-related FNDs are associated with alterations on imaging in the brain's limbic system in general and the amygdala in particular, as well as in the right temporoparietal junction. The temporoparietal junction, he and others found, is a critical node in the experience of voluntary or involuntary movements.
“This patient group turns out to be extremely interesting, in that their abnormal movements look voluntary, but the patients really believe that they are fully involuntary,” Dr. Hallett said. “The question that I asked was, ‘Why don't they experience them as voluntary?’ The fundamental thing we see in these disorders is a problem with the limbic system. The emotional network of the brain is malfunctioning, and that is the underpinning of these disorders.”
A Storied Career
Dr. Hallett's first glimpse of his future career happened in high school, when he chose to write a term paper on Freud for a psychology class.
“Freud was a neurologist who became interested in what was then called hysteria,” Dr. Hallett said. “He eventually called it conversion disorder, which is now what we call functional neurological disorders.”
After obtaining his medical degree at Harvard University, training in neurology at Massachusetts General Hospital, and doing a fellowship in London, Dr. Hallett joined the staff at what was then called the Peter Bent Brigham Hospital. He worked there for eight years and then moved to NIH in 1984. He has served as president of the International Parkinson and Movement Disorder Society, vice president of the AAN, editor in chief of the journal Clinical Neurophysiology, and most recently as inaugural president of the Functional Neurological Disorder Society. Among the members of the new society are not only neurologists but also psychologists, psychiatrists, social workers, and physical and occupational therapists.
“There are very few venues where you can get neurologists and psychiatrists in the same room talking about the same problem,” he said. “People consider neurology and psychiatry to be entirely separate fields, but they're not, really. It's all about the brain.”
Before he and others coined the term FNDs, Dr. Hallett said, many patients took umbrage at being told they had a “psychogenic” movement disorder.
“That's part of the reason we changed the name,” he said. “Things were much worse when it was called psychogenic. Now, when I tell a patient they have a functional disorder, I say, ‘Look, a network in your brain is malfunctioning. We have seen it before; there are causes we understand, and there are ways of dealing with it.’ Then they can accept it.”
Walter Koroshetz, MD, FAAN, director of NINDS, said of Dr. Hallett: “He's been fearless in taking on tough problems. He's trained so many people from around the world who are now making a difference in neurology. People came to the program from India, Japan, Germany, Thailand, Switzerland. For NINDS, Dr. Hallett is really a role model for the special kind of clinical research career one can have at the intramural research program at NINDS in Bethesda.”
Avindra Nath, MD, FAAN, who now has Dr. Hallett's former role as clinical director of NINDS, said that in studying how voluntary movements are initiated in the brain, “Dr. Hallett's really looked at the electrophysiology of free will. He's the seventh-most cited person in neuroscience. He's trained hundreds of people and started a host of societies over the years. What he's done is incredible.”
One of the many international speakers at the day-long meeting celebrating Dr. Hallett's career was Jon Stone, PhD, honorary professor of neurology at the University of Edinburgh, where he has specialized in the study and treatment of FNDs. Appearing remotely since his scheduled flight from the United Kingdom was canceled because of weather, he said directly to Dr. Hallett, “I know how immensely important it has been to the rest of us that you have been such a champion to this field. FND and neuropsychiatry is now one of the 18 core topics that neurologists must know about—something relatively unthinkable 20 years ago, and largely down to your leadership and the work of others.”
For his part, though, Dr. Hallett said, “We're still in this crisis. Doctors don't know how to talk to patients about it. Our treatments are still sub-optimal. And exactly how it happens that the limbic system malfunctions, we still need to learn more about it. There's a lot more work to be done in this area.” He paused and added, “But I'm retiring. I'm 79.”
And then he laughed.