Dementia has been recognized for thousands of years, but the names people used for it shifted dramatically from era to era. Ancient Greeks and Romans described severe cognitive decline with terms like “morosis” and “anoia.” For centuries, everyday language leaned on phrases like “senility,” “dotage,” and “second childhood.” Doctors in the 1800s and early 1900s often recorded “senile dementia” in asylum registers, while the mid-twentieth century popularized “hardening of the arteries” as a catch-all explanation. The word “dementia” itself comes from a Latin root meaning “out of one’s mind,” but it did not settle into medical use until surprisingly late, and its meaning has kept evolving right up to the present day.
Ancient Greek and Roman Terms for Cognitive Decline
Ancient physicians did not have a single, unified label for what we now call dementia. Instead, they drew on several Greek words depending on the symptoms they observed. A review of medical texts from the seventh century BC through the fourteenth century AD found references to “morosis,” “leros” (λήρος, often translated as delirium or nonsense), and “anoia,” all used with medical connotations to describe states of mental deterioration.1PubMed. The ancient history of dementia These terms were not interchangeable. “Morosis” leaned toward foolishness or dullness, “anoia” toward a more complete absence of mind, and “leros” toward rambling or incoherent speech.
What stands out about the ancient record is how little attention severe cognitive loss actually received. A study examining Greco-Roman texts found only four accounts of cognitive loss that might correspond to what modern clinicians would recognize as Alzheimer’s disease or a related dementia.2PubMed. Dementia in the Ancient Greco-Roman World Was Minimally Mentioned Ancient Greeks and Romans generally expected intellectual competence to persist well past age sixty. Some memory loss was acknowledged as part of aging, but the kind of progressive, devastating decline we associate with dementia today was rarely described in detail. That rarity probably reflects shorter average lifespans rather than a belief that the condition did not exist. Fewer people lived long enough to develop late-stage dementia, and those who did were a small and easily overlooked group.
How “Dementia” Entered the Medical Vocabulary
The English word “dementia” traces back to the Latin “demens,” literally meaning “out of one’s mind.” The term surfaced in written records as early as the thirteenth century, but for hundreds of years it belonged to legal and everyday language rather than medicine.3PubMed. History of Dementia A person described as “demens” in a legal proceeding was someone judged incompetent to manage their own affairs. The word carried a broad meaning: it could refer to anyone behaving irrationally, not just someone with progressive brain disease.
The medical meaning took shape during the seventeenth and eighteenth centuries, through the work of physicians like Thomas Willis, David Hartley, and William Cullen. In their usage, dementia came to describe terminal states of behavioral incompetence caused by severe failure of almost any mental function.4Psychological Medicine. Dementia during the seventeenth and eighteenth centuries: a conceptual history This was still a much broader category than today’s definition. It was not yet tied to a particular age group or specifically defined in terms of memory and cognitive deficits. A young person left mentally incapacitated after a fever might be labeled with dementia just as readily as an elderly person losing their memory. The concept was, in one historian’s phrasing, “amorphous,” bundling together what we would now separate into distinct conditions.5PubMed. Evolution in the conceptualization of dementia and Alzheimer’s disease: Greco-Roman period to the 1960s
“Senility,” “Dotage,” and “Second Childhood”
While doctors were slowly working out medical classifications, ordinary people had their own rich vocabulary for age-related mental decline. “Senility” was the most common clinical-sounding term, derived from the Latin “senilis” (of old age). For much of the nineteenth and twentieth centuries, calling someone “senile” was the standard way of describing an older person whose mind was failing. It carried no implication of a specific disease; it simply meant that aging had taken its toll on the brain, as naturally and inevitably as it took its toll on joints and eyesight.
“Dotage” was another widely used word, implying a state of feeble-mindedness brought on by old age. And across centuries of Western literature, one metaphor appeared again and again: old age as a “second childhood.” Scholars and writers from antiquity through the modern era characterized cognitive decline in old people as a return to infant-like dependency and childish behavior.6PubMed. A return to infancy: old age and the second childhood in history The “second childhood” framing drew on humoral theories of aging, on the visible dependency of elderly people who needed care, and on a philosophical idea that the life cycle was circular, returning to its starting point. The stereotype was overwhelmingly negative, though occasionally softened with sentimentality. It persisted because it was easy to grasp and because, for families watching a loved one lose the ability to dress, eat, or recognize them, the comparison to an infant felt viscerally accurate even if it was scientifically meaningless.
These informal labels did real damage. Calling cognitive decline “senility” or “second childhood” reinforced the idea that it was simply what happened when you got old, not a disease that could be studied or treated. That framing discouraged research for decades and made families less likely to seek medical help, since there seemed to be nothing to treat.
The Asylum Era and Nineteenth-Century Labels
By the 1800s, people with severe cognitive decline were increasingly being placed in institutions, and the diagnostic labels of the era reflected how little was understood about their condition. In British lunatic asylums, “dementia” appeared on admission registers as a catch-all for chronic mental deterioration. A review of the Cornwall County Lunatic Asylum’s records from 1873 to 1877 found that among 743 admissions, dementia accounted for about fifteen percent of diagnoses, behind mania but ahead of melancholia.7PubMed Central. Mania, dementia and melancholia in the 1870s: admissions to a Cornwall asylum The clinical descriptions in these records used “dementia” loosely, covering states that modern psychiatry would sort into very different categories.
Older people with dementia occupied an uncomfortable position in the Victorian welfare system. They were admitted to lunatic asylums, workhouses, and charitable homes, but were not truly welcome in any of them. Asylums were meant for people who might recover; workhouses were meant for the able-bodied poor. People described as “the senile” became what one historian called “a perpetual classificatory residuum,” falling through the cracks of every institution’s intended purpose.8PubMed. Institutionalising senile dementia in 19th-century Britain The diagnostic label “senile dementia” itself carried this ambiguity: it implied that the person was old and declining, but offered no prognosis, no treatment plan, and no clear guidance on where they belonged.
“Hardening of the Arteries” and the Vascular Explanation
For much of the twentieth century, the most common explanation for dementia in older people was not Alzheimer’s disease but what doctors and the public called “hardening of the arteries” or, in medical language, “atherosclerotic dementia.” The idea was intuitive: arteries stiffen with age, less blood reaches the brain, and neurons slowly die from starvation. For decades, this was the dominant belief in neurology and in popular culture alike.9Handbook of Clinical Neurology. Vascular cognitive impairment: A preventable component of dementia
The theory collapsed in the 1970s and early 1980s, when cerebral blood flow studies showed that chronic low-grade ischemia was not the culprit. Researchers demonstrated that it was discrete infarcts, essentially small strokes, that caused vascular dementia, not a gradual reduction in blood supply. This led to the concept of “multi-infarct dementia,” which itself was later broadened into “vascular cognitive impairment” as scientists realized that many types of vascular lesions, not just infarcts, could impair thinking.9Handbook of Clinical Neurology. Vascular cognitive impairment: A preventable component of dementia As the vascular theory lost ground, Alzheimer’s disease, which had been considered a rare presenile condition, expanded to fill the space and became almost synonymous with dementia in both medical and popular usage.
Despite being scientifically discredited decades ago, the phrase “hardening of the arteries” persists in everyday conversation, especially among older generations. If you have heard a grandparent or great-grandparent’s decline explained this way, it reflects a mid-century understanding that has since been overturned but never fully replaced in the public imagination.
When Alzheimer’s Disease Got Its Name
The story of Alzheimer’s disease as a named condition begins with Alois Alzheimer, a German psychiatrist who in 1906 presented the case of Auguste Deter, a fifty-one-year-old woman who had developed symptoms of what was then called “presenile dementia,” meaning dementia striking before old age. After her death, Alzheimer examined her brain and identified two distinctive features: senile plaques and neurofibrillary tangles.10PubMed Central. Alois Alzheimer (1864-1915): The Father of Modern Dementia Research and the Discovery of Alzheimer’s Disease His colleague Emil Kraepelin later attached Alzheimer’s name to the condition in a textbook, and “Alzheimer’s disease” entered the medical vocabulary.
For decades, though, Alzheimer’s disease was considered a niche diagnosis, applying only to younger patients with early-onset dementia. Older people with the same symptoms were still labeled with “senile dementia,” as if their condition were fundamentally different simply because of their age. It was not until the 1970s and 1980s that researchers recognized the plaques and tangles Alzheimer had described were present in the brains of elderly dementia patients too. That realization collapsed the artificial distinction between “presenile” and “senile” dementia and turned Alzheimer’s disease into the dominant diagnosis for age-related cognitive decline. The shift happened remarkably quickly: within a couple of decades, “Alzheimer’s” went from an obscure label to the word most people reached for when talking about memory loss in old age.
The DSM-5 and “Major Neurocognitive Disorder”
The most recent major renaming happened in 2013, when the American Psychiatric Association published the fifth edition of its Diagnostic and Statistical Manual of Mental Disorders. The DSM-5 replaced the older category of “delirium, dementia, amnestic and other geriatric cognitive disorders” with a new umbrella term: “neurocognitive disorders.” What had previously been called dementia was relabeled “major neurocognitive disorder.”11PubMed Central. Application of the DSM-5 Criteria for Major Neurocognitive Disorder to Vascular MCI Patients
The rationale was partly scientific and partly about reducing stigma. “Dementia” had accumulated centuries of negative associations, from legal incompetence to asylum confinement to the vague indignity of “senility.” The new terminology also allowed for a milder category, “mild neurocognitive disorder,” capturing people with noticeable cognitive decline who had not yet crossed the threshold into what was formerly called dementia. The classification of dementia in the DSM has evolved across all of its major editions since 1952, reflecting not just advances in brain science but also changing cultural attitudes about aging and mental health.12PubMed. The evolving classification of dementia: placing the DSM-V in a meaningful historical and cultural context and pondering the future of “Alzheimer’s”
In practice, “dementia” has proven hard to dislodge. Most doctors still use it in conversation with patients because it is widely understood. Advocacy organizations like the Alzheimer’s Association have not abandoned the word. And outside of psychiatry, the rest of medicine never adopted “major neurocognitive disorder” with much enthusiasm. The term is technically current in diagnostic manuals, but if your doctor says “dementia,” they are not using an outdated word so much as a more familiar one.
How Ancient Chinese Medicine Described It
The Western history of dementia terminology is only part of the picture. In traditional Chinese medicine, dementia-like symptoms were recorded with a completely different theoretical framework. The earliest Chinese medical references to memory loss date back roughly two thousand years, making them contemporaneous with the Greco-Roman accounts.13PubMed. Traditional Chinese medicine for dementia Chinese physicians attributed the condition to causes like “Brain dystrophy,” “Spleen-Kidney weakness,” “Blood stasis,” and “Phlegm stagnation,” concepts rooted in a medical tradition that understood the body through channels of energy and organ systems that do not map neatly onto Western anatomy.
What is striking is that ancient Chinese descriptions went beyond memory loss. They recognized psychiatric symptoms and sleep disturbances as part of the condition, aspects of dementia that Western medicine only began investigating seriously in recent decades. The Chinese medical tradition did not use a single word equivalent to “dementia,” but its practitioners clearly observed the same cluster of symptoms and tried to explain and treat them within their own system. This is a useful reminder that while the Western terminology for dementia has a long and well-documented history, other medical traditions were grappling with the same human reality under entirely different names.
Why the Old Names Created Lasting Misconceptions
The parade of labels matters because each name carried assumptions that shaped how people thought about the condition and whether they sought help. “Senility” told families that decline was normal aging and not worth a doctor’s visit. “Hardening of the arteries” suggested a plumbing problem with no fix. “Second childhood” framed the person as someone to be managed and pitied rather than treated. Even “Alzheimer’s disease,” for all its scientific grounding, initially created a misleading split between “real” Alzheimer’s in younger patients and ordinary senile decline in older ones.
Each relabeling also reflected genuine progress. Moving from “senility” to “Alzheimer’s disease” meant recognizing a disease process rather than an inevitability. Moving from “atherosclerotic dementia” to specific vascular diagnoses meant more accurate treatment. Moving from “dementia” to “major neurocognitive disorder” at least attempted to reduce the stigma that made people hide symptoms and delay diagnosis. The terminology is still evolving, and in another few decades today’s labels will likely seem as quaint as “dotage” seems now.
Terms You Might Encounter in Old Medical or Family Records
If you are researching a family member’s medical history or reading historical documents, a number of now-obsolete terms may appear. Knowing what they meant in context can help you make sense of what you find.
- Senile dementia: The standard medical diagnosis for age-related cognitive decline through most of the nineteenth and twentieth centuries. It did not distinguish between what we would now call Alzheimer’s disease, vascular dementia, Lewy body dementia, or frontotemporal dementia.
- Presenile dementia: Used for cognitive decline beginning before age 65. This was the original category for Alzheimer’s disease when it was considered a rare, early-onset condition.
- Atherosclerotic dementia: The mid-twentieth-century diagnosis based on the now-disproven theory that chronic reduction in blood flow caused brain deterioration.
- Organic brain syndrome: A broad label used in mid-twentieth-century psychiatry to distinguish brain-based conditions from “functional” mental illnesses like schizophrenia or depression. Dementia often fell under this heading.
- Chronic brain syndrome: A close relative of organic brain syndrome, emphasizing that the cognitive impairment was irreversible. Used in asylum and hospital records through the mid-1900s.
- Dotage: An informal term implying feeble-mindedness in old age. Common in literary and legal contexts rather than medical ones.
These labels tell you something about the era’s understanding, but they rarely tell you the specific disease a person had. A diagnosis of “senile dementia” in a 1940s hospital record could correspond to any of several conditions we now distinguish. Interpreting old records requires accepting that diagnostic precision simply was not available.
The Gap Between Professional and Popular Language
One reason the history of dementia terminology feels so tangled is that professional and popular language have always moved at different speeds. Doctors abandoned “atherosclerotic dementia” in the 1980s, but “hardening of the arteries” persisted in family conversations for another generation. The DSM replaced “dementia” with “major neurocognitive disorder” in 2013, but the word “dementia” remains dominant everywhere outside psychiatric coding manuals. “Senility” lost its clinical standing decades ago, yet plenty of people still use it without realizing it implies something outdated, namely that cognitive decline is a normal part of getting old rather than a symptom of disease.
This lag is not just a curiosity. When popular language trails behind science, it perpetuates old assumptions. A person who thinks of their parent’s condition as “just senility” is less likely to pursue a specific diagnosis, which means less likely to receive targeted treatment, participate in clinical trials, or benefit from support services designed for specific types of dementia. The words we use shape the care we seek, and the old names carried built-in reasons not to seek it at all.