There is a current paper written by Kenneth Kendler on
metaphorical brain talk in psychiatry (1).
It is open access and I encourage people to read it. I automatically read anything written by
Kendler because he is probably my last remaining hero. That is ironic given that he is only slightly
older than me. If you are not familiar
with his work there is a Wiki
page that will partially bring you up to speed. I have referenced him many times on this
blog. His writing is consistently next
level when it comes to psychiatric research and theory. If you find yourself reading collections of “greatest
papers in psychiatry” and don’t find his work there. Throw that collection away and read Kendler.
In this paper he reviews the history of metaphorical
brain talk (MBT) in psychiatry and what he sees as four implications for
the field. He defines this as describing the altered brain function is
psychiatric disturbances in a way that seems explanatory but have no
explanatory power. Examples would
include the infamous chemical imbalance trope. He reviews MBT across discrete periods in
psychiatric history and gives examples in each one of these time frames. Since this is an open access paper – I
encourage any interested readers to look at all the examples. I will touch on a few points that I find
interesting.
He first reviews Asylum Psychiatry from 1790-1900. Several authors wrote about conditions they
observed in their patients using descriptive phrases like brain excitement,
disordered nervous system, morbid action of vesicular neurine, peculiar
and special force in the cerebral masses, excitement and vividness
always emanate from one portion or spot of the brain, etc. On the one hand the metaphors are obvious and
consistent with Kendler’s characterization that they are biologically
meaningless. On the other the images are
vague and the significant part of the metaphor is descriptive language of
mental activity.
In other writing Kendler has referred to this era is
psychiatry as the era of protopsychiatrists. I have reviewed that
history on this blog and agree that psychiatry as the profession we know today
probably did not start until the 1920s in the US even though it was well
established in Europe for a longer period.
The European version included physicians who were also described as
neurologists, neuropathologists, psychiatrists, psychologists, and
alienists. If you read references to
these physicians today – the descriptions are often interchangeable and
research is required to clarify their qualifications and training.
There was more going on during this period than meaningless
metaphors. Alois Alzheimer was a psychiatrist
and neuropathologist (11). Between 1891
and 1907, Alzheimer described several neurodegenerative diseases including vascular
dementias and the disorder that would eventually come to be known as Alzheimer’s
disease along with the clinical correlations of memory loss, inadequate self-care,
and paranoia. Otto Binswanger (1852-1929) was a Swiss psychiatrist,
neurologist, and neuropathologist who was also active at the time. In 1894, he
described “encephalitis subcorticalis chronica progressive” while attempting to
differentiate types of dementia from dementia caused by tertiary syphilis that
was called general paresis of the insane or GPI at the time. GPI was a very common reason for
institutionalization at the time accounting for 20% of admission and 34% of the
death in asylums in the 19th and early 20th century before the advent of
antibiotics. Both Alzheimer’s Disease
and Binswanger’s Disease remain controversial entities to this day in terms of
the definitive neuropathology and likely etiopathogenesis. An important historical lesson is that these
early psychiatric researchers did practice psychiatry while doing
neuropathology and often had students who went on to have significant
contributions to the field outside of neuroanatomy. In the case of Alzheimer, Franz Nissl
(1869-1919) became his longtime collaborator and head of the Psychiatric Clinic
at the University of Heidelberg where Karl Jaspers (1883-1969) was his student. Jaspers wrote his text General
Psychopathology while working for Nissl.
His next historical period is The First Biological
Revolution in Psychiatry 1870s – 1880s.
Griesinger was a key figure and his central thesis that mental illnesses
were brain diseases. He also published
an influential textbook and journal. His
students promoted neuropathological research through autopsies as the primary
method of scientific inquiry during that period. Kendler concludes that this
method of research was a dead end for classical psychiatric disorders – but
there seems to be more going on in the field than that. Several of these physicians over the next 50
years identified themselves not just as psychiatrists but also neurologists and
neuropathologists. Otto Binswanger ((1852–1929) and Wilhelm Griesinger
(1817-1868) were designated as neurologists
and psychiatrists. Freud (1856-1939)
did 6 years of basic research in comparative neuroanatomy, published a
monograph on aphasia (6) wherein he coined the term agnosia, and was a
Privadozent in neuropathology. All of
that before he invented psychoanalysis.
The Reaction to
the Revolution 1880-1910 is described next with a critique by Kraepelin of
excessive and speculative biological theories of psychiatric disorders. The critique largely is focused on Meynert’s
(1833-1891) work. The critiques focus
primarily on highly speculative hypotheses based on neuroanatomy. Meynert’s
neuroanatomy work and that of his colleagues and students is still recognized
today (2-4). His poetic license may have
been excessive, but the neuroanatomy was solid.
Metaphorical Brian Talk of the 20th Century focuses
initially in Adolf Meyer. Like the other psychiatrists discussed so far,
Meyer had additional skills and was employed as a neuropathologist
following his emigration to the United States from Switzerland. He
famously said: “My entrance into psychiatry was through the autopsy room”(8). Meyer had an indirect link to Meynert because
his supervisor August Forel was one of Meynert’s students. A quote is included from a 1907 paper in
which Meyer suggests that early American psychiatrists:
“…pass at once to a one-sided consideration of the
extra-psychological components of the situation, abandon the ground of
controllable observation, translate what they see into a jargon of wholly
uncontrollable brain-mythology, and all that with the conviction that this is
the only admissible and scientific way.”
Meyer is credited with psychobiology model of
psychiatry. He saw the brain and mind as
an evolved unitary and dynamic structure reacting to the environment. As such it would not necessarily show typical
disease related changes at the gross or microscopic levels and could only be
studied if environmental and social variables were considered.
Meyer’s psychobiology approach championed a detailed
clinical approach to psychiatric disorders and avoidance of biological
reductionism. That would put Meyer along
with Kraepelin squarely in the camp against not only MBT but also any theory
suggesting that there was a direct biological explanation for mental behavior
or psychiatric disorders. Both were trained as neuropathologists and Kraepelin
worked with Alzheimer. That would seem to lend a measure of credibility to
their concerns.
Kendler ends that section with a quote from Jaspers that the
neuroanatomy discovered by the neuropsychiatrists is one thing but it cannot
possible be correlated with mental phenomenon.
He refers to this as “brain mythologies”. Meyer’s and Karl Jasper’s approached have
been credited by McHugh and Slavney in their comprehensive 4 perspective
approach to mental disorders (7).
Kendler concludes that the metaphorical brain talk in
psychiatry arises from several sources.
First, our identity as physicians dictates that like other specialists,
we need an organ to focus on and that has been the brain. That relationship was
impacted by neurology seeming to take over conditions with overt and definable
brain pathology. He concedes that there
is overwhelming evidence that psychiatric disorders arise in the brain (in fact
he is a world expert in this) but there are still no specific mechanisms. MBT is one way to address that fact. He defers to a historian that this may be status
anxiety relative to other specialties with more definable pathology and in
some cases mechanisms and MBT is a way to address that. His own take on MBT is much more reasonable
when he describes it as a wish that at some point we will get to the
deeper understanding of the brain that we all seek.
Despite the historical digressions, Kendler comes to the
same conclusion that I did decades ago. We
do not have to make things up in discussions with patients and we do not need
to use metaphors devoid of biological reality.
That does not mean there is no room for real brain talk – the kind that
occurs when you are discussing the effects of brain trauma, strokes, dementia,
epilepsy, and endocrinopathies. It does
mean that you can flatly say for any diagnosis there is no known etiology but
the research supports this treatment plan and beyond you can provide a
discussion or references to the latest research.
The explanatory gap in psychiatry between the biological
substrate and mental life or associated disorder is obviously there but it is
present in every other organ system to one degree or another. It is quite easy to pretend that basic
medical conditions like asthma or diabetes have all been worked out with
biologically precise mechanisms of action – but nothing could be farther from
the truth. Endophenotypes exist for both
conditions, most people are symptomatic despite treatment, and death still
occurs even in mild cases. There is a definite dynamic of idealizing medical
conditions as completely knowable and treatable – when they are not. In those cases, the explanatory gap is very basic
between biology and wheezing or blood glucose. In the case of psychiatric
disorders – many more symptoms and ordinary functions are across that gap. The explanation is much harder and any
symptoms are less clearly rooted in biology.
I am less concerned about the effects of MBT and how it
potentially affects understanding the mental life of our individual patients. That is what psychiatrists are trained to
do. We are face-to-face with a person
who we are supposed to help and, in that situation, it is doubtful that MBT
will add much.
There are a few other reasons that may have facilitated MBT
in the historical contexts discussed. Rhetoric is a powerful and rarely
discussed aspect of the scientific and medical literature. The metaphor users were all active
neuroscientists in their day. As such
they were likely competing for positions, labs, associations, recognition, and
funding. This is commonly how rhetoric
occurs in research communities and scientific literature.
A related issue is
personality and notoriety. It is rare to see much commentary about these issues
with 19th and 20th century scientists.
Once a certain level of fame is reached, are you more likely to
speculate and theorize? Can some of those
speculations take on the form of MBT?
One of the most criticized neuropsychiatrists in this paper was Meynert
for suggesting overly elaborate mechanisms that had no basis in science. On the other hand, Meynert is still renowned
for some of his neuroanatomical findings (4).
Is it possible that a scientist with that level of accomplishment did
not care about the difference between speculation and scientific findings? Is it possible that his students and post
docs encouraged him to speculate beyond his findings – just brainstorming? Is
he just taking a chance that he might be correct in order get credit for an
innovative finding? I suppose a
translation of his book might offer a few addition clues, but the reason I have
these suggestions is that I have seen this happen in current times. We might reassure ourselves that our
publications are not suffering from metaphorical overreach but problems with
irreproducible findings suggest otherwise.
The state of neuroscience for much of the timeline of this
paper could be a factor. Not a lot was
known about neurons or neuronal transmission.
Neuron theory and the term neuron did not happen until 1891. I have a
slightly different take on the history of psychiatry in the US and how
psychiatry and neurology split. Until
1934, most psychiatrists were also practicing neurology. Many were
self-designated as neuropsychiatrists.
The ABPN decided to require board exams in both neurology and psychiatry
to practice both and at that time psychiatry began to grow disproportionately
relative to neurology. It is still
possible to be doubled boarded in both. It is also possible to practice
neuropsychiatry or medical psychiatry based on residency training and
practice. I have long promoted the idea
that modern day psychiatrists should practice intellectually interesting
psychiatry and for me that uses the DSM as a scope of practice specifier and
knowing all the medicine and neurology necessary to care of those
patients.
Revisiting the main point of Kendler’s paper. In his summary he states his major concern
has been an impoverished conceptual foundation in the field based on a brain
centric focus and metaphorical talk about it.
I agree with anything metaphorical and on this blog have numerous posts
addressing the chemical imbalance and biomedical metaphors being
paced upon us by our critics. In many
ways – I don’t think the clinical brain focus has been enough.
Psychiatrists need to be able to rapidly recognize neurological and medical
emergencies in addition to the medical and neurological causes of psychiatric
syndromes. Psychiatrists need to be able to diagnose aphasias as well as
they can diagnose thought disorders.
Those skills can all be traced back to late 19th century and
early 20th century psychiatry. I also see that era as precipitating
controversy, dialogue, and pendulum swinging so far in the other direction that
at one point the medical internship was temporarily removed from residency
programs.
The reality is that we will see people referred to us or
walking in off the street who have brain lesions and/or medical problems or not.
They will generally have a psychiatric problem that has been assessed and
treated by several other people that did not work. Our job is to do a thorough
assessment of their physical and mental problem and come up with a plan – even
when there is no known treatment. That
plan includes relationship building, helping them be more competent, and
helping them make sense of their world.
All the irrelevant metaphors can easily be ignored.
George Dawson, MD, DFAPA
1: Kendler KS. A
history of metaphorical brain talk in psychiatry. Mol Psychiatry. 2025
Aug;30(8):3774-3780. doi: 10.1038/s41380-025-03053-6. Epub 2025 May 13. PMID:
40360726; PMCID: PMC12240831.
2: Liu AK, Chang RC,
Pearce RK, Gentleman SM. Nucleus basalis of Meynert revisited: anatomy, history
and differential involvement in Alzheimer's and Parkinson's disease. Acta
Neuropathol. 2015 Apr;129(4):527-40. doi: 10.1007/s00401-015-1392-5. Epub 2015
Jan 30. PMID: 25633602; PMCID: PMC4366544.
3: Meynert T, Putnam
J (translated) (1872) The brain of mammals. In: Stricker S (ed) A Man. Histol.
W. Wood & company, New York, pp 650–766
4: Judaš M, Sedmak G,
Pletikos M. Early history of subplate and interstitial neurons: from Theodor
Meynert (1867) to the discovery of the subplate zone (1974). J Anat. 2010
Oct;217(4):344-67. doi: 10.1111/j.1469-7580.2010.01283.x. PMID: 20979585;
PMCID: PMC2992413.
“The presence of neurons in the subcortical white matter
of the human brain was first described and illustrated by Theodor Meynert in
1867, and additionally commented on in his subsequent publications (Meynert,
1867, 1872, 1884). Meynert illustrated these cells in both superior frontal
(Fig. 1A) and primary visual (Fig. 1B) human cortex and pointed out that these
are spindle-shaped (fusiform) neurons which are oriented vertically to the pial
surface within the gyral crowns, but horizontally at the bottom of sulci. He
also suggested that they have a special functional relationship to short
corticocortical association fibres (fibrae arcuatae, or Meynert's U-fibres) and
that these fusiform cells may therefore be regarded as intercalated cells of
his Associations system of short corticocortical fibres (Meynert, 1872).”
5: Cowan WM, Kandel
ER. A brief history of synapses and
synaptic transmission. In: Cowan WM,
Sudhof TC, Stevens CF. Synapses. The
Johns Hopkins University Press, Baltimore, 2001. pp. 3-87.
6: Freud S. On aphasia: a critical study. International Universities Press. New York,
1953. Translation of 1891 German
publication and introduction by E. Stengel.
7: McHugh PR, Slavney
PR: The Perspectives of Psychiatry, 2nd ed. Baltimore, Johns Hopkins
University Press, 1998
8: Lamb S. Social
Skills: Adolf Meyer's Revision of Clinical Skill for the New Psychiatry of the
Twentieth Century. Med Hist. 2015 Jul;59(3):443-64. doi: 10.1017/mdh.2015.29.
PMID: 26090738; PMCID: PMC4597240.
9: Lamb S. Pathologist of the Mind – Adolf Meyer and the
Origins of American Psychiatry. Johns
Hopkins University Press,Baltimore, 2014. p. 255.
10: Rutter M.
Meyerian psychobiology, personality development, and the role of life
experiences. Am J Psychiatry. 1986 Sep;143(9):1077-87. doi:
10.1176/ajp.143.9.1077. PMID: 3529992.
11: Goedert M, Ghetti
B. Alois Alzheimer: his life and times. Brain Pathol. 2007 Jan;17(1):57-62.
doi: 10.1111/j.1750-3639.2007.00056.x. PMID: 17493039; PMCID: PMC8095522.
Photo Credit:
I thank my colleague Eduardo Colon, MD for the surreal photo of the Foshay building in Minneapolis.
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