In our last post, we explored Avicenna’s sophisticated understanding of mental health. Today, I want to start tracing how we got from his nuanced holistic framework to our modern categories—because it’s a fascinating journey through changing ideas about the mind and body, and what it means to be human. To do this in an post instead of a semester-long course, though, means we’ll barely skim the surface of 900 years of medicine. Along the way, I’m skipping over interesting and relevant concepts like acedia, and important figures like Ishaq ibn Imran and Robert Burton—and I feel bad for doing so. Apologies to all the unmentioned academics, and the medieval monks who hand-copied manuscripts – but most especially, apologies to the countless unnamed women healers, herbalists, midwives, and barber-surgeons who actually kept people alive while the ‘professionals’ debated humors and the nature of existence.
After Avicenna’s death in 1037, his Canon of Medicine shaped how physicians understood and treated disease for nearly five centuries. But the Renaissance marked a turning point, as scholars began approaching Avicenna’s work not as unchangeable truth but as a foundation to be tested against their own observations. The rediscovery of ancient texts beyond Galen and Avicenna, coupled with the rise of humanism, brought a new wave of intellectual curiosity that would revolutionize medicine. Thinkers of the time sought to recover and critically engage with the works of ancient authorities, challenging the medieval reliance on secondhand interpretations.
Before the Renaissance, medical education in Europe was a tightly controlled and largely theoretical enterprise. It revolved around the study of texts, particularly the works of Galen, Avicenna, and a handful of other authorities. These texts were taught in newly formed universities where aspiring physicians spent years memorizing their contents. Medical students were rarely encouraged to question these teachings; instead, their role was to master established doctrines and apply them to practice.
Dissection was nearly absent or highly restricted. When performed, dissections served less as investigative tools and more as demonstrations to reinforce existing theories. A professor would often read from Galen’s texts while a barber-surgeon conducted the dissection—any inconsistencies were dismissed as errors of the body being examined, not the texts themselves. The mind-body interplay described in Galenic and Avicennian frameworks, especially through the lens of humors and spirits, was accepted without significant challenge.
This lengthy, highly textual and hierarchical approach to learning meant that medical education was restricted to the elite, and lagged behind practical needs. While medieval universities emphasized theoretical knowledge, much of the day-to-day healing work was carried out by folk practitioners, midwives, and barber-surgeons who operated outside the university system. Their empirical methods and hands-on experience were rarely acknowledged by academic physicians, who saw themselves as stewards of ancient wisdom rather than pioneers of new medical discoveries.
When the Renaissance sparked a revival of ancient texts and a renewed emphasis on direct observation, it began to disrupt this static system. Physicians like Andreas Vesalius didn’t just reintroduce dissection as an educational tool—they reframed it as a way to challenge, refine, and sometimes overturn traditional knowledge. Medical education shifted slowly but profoundly, moving away from rigid textual study toward a more dynamic interplay of theory and practice. This transition was neither smooth nor uniform. While some institutions embraced these changes, others clung to Galenic orthodoxy, reluctant to abandon the frameworks that had defined medicine for centuries. The result was a period of intellectual tension, where old and new ideas collided and reshaped the landscape of medical education.
Hippocrates reemerged as a pivotal figure. His writings emphasized clinical observation and the body’s natural healing processes, offering an empirical approach distinct from Galen’s more theoretical frameworks. Dioscorides’s De Materia Medica inspired a resurgence in botanical medicine, spurring the creation of richly illustrated herbals that merged ancient knowledge with new discoveries. Even Aristotle’s biological treatises, long overshadowed by Galen’s dominance, were reevaluated for their insights into anatomy and function.
These rediscovered texts reached Europe through multiple channels. The Byzantine Empire had preserved many Greek manuscripts, which found their way west after the fall of Constantinople in 1453. Meanwhile, Arabic scholars like Al-Razi and Avicenna had expanded upon Greek medicine during the Islamic Golden Age, and their translations further bridged the knowledge gap. By the late 15th century, the printing press ensured knowledge could spread rapidly, breaking the constraints of monastic libraries and university lecterns.
This revival didn’t just add more books to doctors’ shelves—it fundamentally changed how medicine was practiced. Physicians like Andreas Vesalius, inspired by this new access to ancient texts, began questioning Galenic orthodoxy. Vesalius’s De Humani Corporis Fabrica (1543), based on meticulous dissections, revealed numerous errors in Galen’s anatomy and set a new standard for empirical observation. It was a move that signaled a shift: rather than merely inheriting wisdom, physicians were now expected to test it.
Yet the Renaissance also highlighted a growing tension. The rediscovery of ancient texts emphasized the complexities of humoral theory and the interconnectedness of mind and body. However, these frameworks began to coexist uneasily with emerging mechanistic views of the body. Physicians grappled with questions about how these diverse traditions could be integrated. While Galen and Avicenna still held authority, their frameworks were evolving, enriched by fresh perspectives but increasingly challenged by direct observation and experimentation. Renaissance humanism, with its emphasis on revisiting original texts and questioning established authority, created fertile ground for these shifts to take root. This fusion of ancient knowledge and Renaissance innovation brought a new dynamism to medicine. But as we’ll see, it also set the stage for deeper conflicts—ones that continue to shape how we think about the mind, body, and their interconnectedness.
Enter René Descartes (1596-1650), whose impact on how we think about mental illness cannot be overstated. His philosophical proposition “I think, therefore I am” might seem abstract, but it revolutionized medicine by separating mind from body. The body became res extensa – extended material substance operating by mechanical principles, while the mind became res cogitans – thinking substance operating by different rules entirely. This Cartesian split had profound implications for understanding mental health. If the body was just a machine, then physical symptoms needed mechanical explanations. If the mind was separate, then mental symptoms belonged to a different realm entirely.
The mechanistic view gained momentum through the 18th century as early experiments with electricity seemed to confirm the body’s machine-like nature. Luigi Galvani’s famous experiments with frog legs in the 1780s suggested that electrical forces animated living tissue. The nervous system began to be understood as a kind of electrical network, leading to new theories about how it might malfunction.But this mechanical model left many physicians unsatisfied. It couldn’t explain the subtle interactions between mental and physical symptoms that they observed in their practices. It didn’t account for how emotions affected physical health or how bodily conditions influenced mental state. Most importantly, it failed to explain why the same “mechanical” problem could manifest so differently in different people.
The 19th century brought interesting attempts to resolve these contradictions. The concept of “neurasthenia” emerged – a diagnosis characterized by persistent physical and mental exhaustion that physicians believed stemmed from a depletion of the nervous system’s energy. George Beard, who popularized the diagnosis in the 1860s, saw it as a distinctly modern illness – the result of urbanization, industrialization, and the increasing pace of life literally depleting people’s “nerve force.”
Neurasthenia became a fashionable diagnosis, particularly among the urban middle and upper classes and largely reflected cultural anxieties about modernity. The idea that civilization itself could make people sick represented a kind of pushback against unchecked progress. The prescribed treatments – returning to nature, slowing down, rebuilding vital force gradually – reflected a longing for simpler times.
The neurasthenia diagnosis also revealed deep gender biases in 19th century medicine. Women with neurasthenia were often prescribed complete bed rest and isolation – the infamous “rest cure” popularized by Silas Weir Mitchell. Men, on the other hand, were more likely to be prescribed outdoor activity and vigorous exercise – the “West cure” that involved ranching or hunting in frontier territories. These gendered treatments reflected and reinforced cultural power structures. For upper-class women, the label of neurasthenia often served to medicalize and control behavior that challenged Victorian gender norms – particularly intellectual or professional ambitions. The prescribed rest cures effectively removed women from public life and reinforced their confinement to domestic spaces. Meanwhile, working-class women suffering similar symptoms rarely received the neurasthenia diagnosis, instead facing accusations of hysteria or moral weakness. This class disparity reveals how neurasthenia, like many medical diagnoses of its era (and some today), functioned as both a medical category and a tool of social control.
Meanwhile, early psychiatry was developing in asylums and hospitals, creating new frameworks for understanding mental illness. The work of pioneers like Philippe Pinel (1745-1826) began shifting views of mental illness from moral or spiritual failings to medical conditions requiring humane treatment. This medicalization of mental illness was double-edged – it reduced stigma but also sometimes reduced complex human experiences to simple disease categories.
We will explore some of the early modern roots more deeply but if you haven’t figured it out by now, I think something important was lost in this evolution. Where Avicenna, Burton and others saw complex patterns requiring individualized approaches, later frameworks tried to reduce everything to simpler models – whether mechanical, electrical, or neurological. The nuanced understanding of different depression patterns and their various causes began to flatten into more standardized categories.
This tension – between reducing mental illness to simple models and recognizing its true complexity – continues to shape psychiatry today. Our modern frameworks are in many ways still grappling with Descartes’ mind-body split. We still struggle to bridge the gap between biological and experiential understandings of depression.
In our next post, we’ll explore more about how these changes eventually led to our modern understanding of depression. But for now, I invite you to reflect on what would it take to fully transcend the Cartesian split and embrace a unified view of the human experience in health care?
With appreciation for our complex history,
-Thomas