A Neurology and Psychiatry Merger: Quest for the Inevitable?

Inevitably Separate or Inevitably Merged?

The fields’ differences tend to loom larger than their similarities for many who weigh in on this issue, however.

“The skill sets are very different,” Dr Elliott told Neurology Advisor. “Yes, in theory overlapping them makes a lot of sense, but very different types of people get pulled to the two.” Except where medication is involved, “the psychiatric approach to diagnosis and treatment is quite different from the neurology approach,” he said. Bridging such a gap likely also means sacrificing something from both because only so much time exists for training, and neurology and psychiatry already each comprise major components of schools’ core curricula, he said.

Some, such as Dr Reilly, see so little distinction that they insist a single discipline is ideal. Others take a more measured approach, such as Carole Azuar and Richard Levy, MD, PhD, both in the department of neurology at Pitié-Salpêtrière Hospital in Paris, France.4 They argue that the advances of neuroscience have made it important at least to get the 2 disciplines talking more to one another.

“The behavioral symptoms that lie along the borders of both neurology and psychiatry by their expression and their underlying diseases have remained in the ‘blind spots’ of both disciplines,” they write. Patients with disorders whose symptoms may fall under neurology and psychiatry are often neglected, shuttled only toward one specialist, or receive disjointed care without discussion between their neurologist and psychiatrist. That occurs despite the recognition that behavioral disorders in general often arise from a combination of brain dysfunction and genetic, sensory, somatic, and/or environmental factors.

“The patients that are really hurt are the ones that fall between the cracks because we’re not sure what’s going on, and that happens in both disciplines,” Dr Elliott agreed.

The resulting knowledge gap has led to poor clinical characterization, limited care, inadequate knowledge about pathophysiology, and lack of teaching about these disorders, Ms Azuar and Dr Levy write. Yet clinical neuroscience can help “neurologists and psychiatrists to again speak a common language so that, together, they can now address the pathology of neuropsychiatric disorders.”

Bringing neurology and psychiatry together may also begin to address the “reproducibility crisis” that has plagued behavioral science particularly in recent years.⁶ Although many factors likely contribute to replication problems, “inadequate validation of laboratory-specific testing conditions” is a common cause, particularly in behavioral research, suggests Anne M. Andrews, PhD, and her colleagues at the University of California at Los Angeles.⁷ The use of rigorous, specific criteria and validation techniques that Andrews et al recommend would bring behavioral and psychiatric research closer to the objectivity seen in neurology research (although Andrews et al and others note that all disciplines could benefit from greater rigor).

Indeed, “we may be forced to come together in ways we wouldn’t have before,” Dr Elliott said, as a result of advances in psychiatric biomarkers and brain-region treatments. He noted that psychiatry has led the way with transcranial magnetic stimulation, but neurologists excel more at understanding the anatomy of the brain, a necessary skill for such treatments. He still expects conditions such as schizophrenia and autism, where MRI has begun to elucidate mechanisms, to require psychiatrists because they are trained to help families and patients manage behavioral issues that neurologists usually avoid.

Even still, some conditions blend the fields anyway, such as dementias. Neurologists tend to document the type of dementia and treat its progression whereas geriatric psychiatrists manage comorbid conditions and family systems issues, Dr Elliott said.

Perhaps it is that tension between undeniable differences and inevitable merging that has led to more recent calls for cross-disciplinary cooperation.

Making Synergy Happen

Dr Reilly does not propose a specific way to merge the disciplines, but several others have. Ms Azuar and Dr Levy focus on apathy and agitation/aggression as models for describing behavioral disorders and present 2 case studies that illustrate the need for synergy between neurology and psychiatry to reach accurate diagnoses.

Ibáñez et al suggest a neuropsychiatric approach to triangulate social neuroscience with neurology and psychiatry to better understand the “impaired social brain.”3 They discuss key domains of social neuroscience — facial emotion recognition, empathy, theory of mind, moral cognition, and ecologic assessment of social context — and note that disturbances in various neural networks lead to social cognition deficits in both neurologic and psychiatric disorders. Essentially, they argue that synergy among all 3 of these fields is necessary to fully understand and treat conditions involving social deficits.

Ibáñez et al acknowledge the hurdles in such a path, particularly in terms of the hyperspecialization that dominates clinical care, research funding, and academic programs. “A systematic triangulation can only become concrete if major educational and political changes are progressively made,” they write. “Even if shared social cognition impairments in neurological and psychiatric disorders are already broadly acknowledged, implementing this conception at an institutional level will constitute a major challenge.”3

Some US institutions already have neuropsychiatric units or have similarly combined neurology and psychiatry, such as the pediatric clinic at Stanford led by Lawrence Fung, MD, PhD, Dr Elliott said. However, academic politics and power issues are likely to complicate many such attempts, as are continued disparities in reimbursement for neurologic interventions compared with psychiatric ones, Dr Elliott added.

“When you’re talking about ‘coming together,’ it becomes a matter of whether it’s a merging of equals or of one profession getting swallowed up by another,” he told Neurology Advisor. “That’s the fear that keeps the 2 fields apart. If you have a combined department that was headed by a psychiatrist or neurologist, you might find that it’s not an equal distribution of resources in terms of what’s valued and what’s not.”

Perminder Sachdev, MD, PhD, FRANZCP, and Adith Mohan, MRCPsych, FRANZCP, of the University of South Wales and The Prince of Wales Hospital in Sydney, Australia, have taken a step toward tackling such a challenge by creating a third option in their “International Curriculum for Neuropsychiatry and Behavioral Neurology.”2 They don’t propose a complete merging of the fields but rather an advanced curriculum of neuropsychiatry grounded in a firm education of both neurology and psychiatry. They acknowledge differences between the fields that Dr Reilly dismisses or overlooks and emphasize the need for a third specialty encompassing skill sets and approaches from both.

“Psychiatry prides itself in its rich phenomenological descriptions, nuanced observation of behavior, highly sophisticated interviewing skills, interpersonal sensitivity, ability to deal with ambiguity, and the seamless synthesis of the biological with the psychological,” and “only an exclusive training in psychiatry can deliver competence of all this,” Drs Sachdev and Mohan write. “Neurology lays claim to its unabashed empiricism, rigorous clinical examination skills, and its pure objectivity, again requiring considerable exposure and training in the traditional subject matter.”2

Hence, they have mapped out an extensive framework — including the territory, objectives, skills, competencies, and training — for a curriculum in neuropsychiatry, which is functionally indistinguishable from behavioral neurology, they note.

However it occurs, greater interaction between the 2 fields does seem inevitable, Dr Elliott says. The way it plays out, both in the United States and globally, will likely depend as much on cultural factors as on advancements in technology and understanding of the brain.

References

1. Reilly TJ. The neurology-psychiatry divide: a thought experiment. BJPsych Bull. 2015;39(3):134-135.

2. Sachdev P, Mohan A. An international curriculum for neuropsychiatry and behavioural neurology. Rev Colomb Psiquiatr. 2017;46 Suppl 1:18-27.

3. Ibáñez A, García AM, Esteves S, et al. Social neuroscience: undoing the schism between neurology and psychiatry. Soc Neurosci. 2018;13(1):1-39.

4. Azuar C, Levy R. Behavioral disorders: The ‘blind spot’ of neurology and psychiatry. Rev Neurol (Paris). 2018;174(4):182-189.

5. US National Library of Medicine. Conversion Disorder. Medline Plus. https://medlineplus.gov/ency/article/000954.htm. Updated January 28, 2019. Accessed February 5, 2019.

6. Nosek BA, Cohoon J, Kidwell MC, Spies JR. Estimating the Reproducibility of Psychological Science. Open Science Collaboration. https://osf.io/ezum7/. Updated September 18, 2018. Accessed February 5, 2019.

7. Andrews AM, Cheng X, Altieri SC, Yang H. Bad behavior: improving reproducibility in behavior testing. ACS Chem Neurosci. 2018;9(8):1904-1906.