How Senility and Dementia Differ

Inaccurate definitions can cause confusion and misperceptions

"Senility" is a term that can mean anything related to old age. For instance, senile arthritis is a joint disease that arises in one's senior years.

"Senile" and "senility," though, are more commonly used to describe age-related cognitive decline—as in senile Alzheimer's, senile dementia, and senile plaques.

However, the use of the word "senility" has fallen out of favor over the years. Memory loss or confusion that occurs with old age is currently referred to as dementia.

This article discusses senility and why the term was replaced with "dementia." It also explains what causes dementia, how it is diagnosed, and what you can do to try to prevent it.

Two doctors studying images of the brain
Monty Rakusen Cultura / Getty Images

What Does 'Senile' Mean?

"Senile" was used more commonly in the past, especially when memory loss and confusion were thought of, by some, as a normal consequence of getting older. The view used to be that the body and the mind both could be expected to decline together as someone aged and that poor mental functioning was just a normal part of aging.

An individual was often described as having "senile dementia" or "senile Alzheimer's," meaning that the disease and its associated mental decline developed in older age.

Although still occasionally used, this term has lost its popularity, partly because it has a negative, disrespectful tone, as in, "The old man is senile."

Science has shown that significant memory loss, disorientation, and confusion are not normal parts of aging, but rather are symptoms of neurocognitive disorders such as Alzheimer's diseasevascular dementia, frontotemporal dementia, or Lewy body dementia.

The term "senile" is sometimes used to describe the plaques that build up in the brain as Alzheimer's disease progresses. These senile plaques, along with neurofibrillary tangles, are often described as the hallmarks of Alzheimer's disease,

Senility vs. Dementia

While senility is a loosely used and somewhat inaccurate and negative reference to cognitive loss, "dementia" is the accepted medical term.

Senile dementia of Alzheimer's type (SDAT) is a medical diagnosis that previously was used to describe symptoms of dementia that were likely caused by Alzheimer's disease. The word "senile" here references the age of onset, which was considered senile if it had developed after the age of 65.

The descriptor "late-onset" (vs. early onset) is now more commonly used if someone is identifying the age of onset of dementia.

The word "type" was included in the diagnosis because Alzheimer's technically could only be definitively diagnosed following a brain autopsy after death, so the implication was that the symptoms appeared consistent with those of Alzheimer's disease.

According to the Diagnostic and Statistical Manual-V (DSM-V), SDAT is now coded diagnostically as either a major or minor neurocognitive disorder due to Alzheimer's disease.

Causes and Stages of Dementia

Dementia includes a broad range of brain conditions that cause a progressive decline in a person's ability to think and remember. Moreover, the loss of these abilities makes it increasingly difficult for people to function or care for themselves.

The most common causes of dementia include:

  • Alzheimer's disease
  • Vascular dementia
  • Lewy body dementia
  • Orontotemporal dementia

Other less common causes include:

There is no cure for dementia, and the progression of the condition is typically slow. Medical professionals usually classify dementia by stage based on symptoms. 

Stages may be classified as follows:

  • Early-stage dementia is diagnosed when daily life is starting to become impacted. It is usually characterized by forgetfulness, inability to find words, repeating things, and difficulty in managing routine tasks like finances or shopping.
  • Middle-stage dementia will affect a person's ability to function both inside and outside of the home. A person will typically lose almost all new information within moments of receiving it, exhibit impairment of social judgment and general problem-solving, and will often get lost. Challenging behaviors (e.g., disruptive or inappropriate) often develop in mid-stage dementia.
  • Late-stage dementia is the stage where a person requires assistance with all activities of daily living, such as eating, bathing, and dressing. 

What Are the Warning Signs of Dementia?

According to the Centers for Disease Control and Prevention, the following may indicate dementia:

  • Forgetfulness
  • Depression
  • Withdrawal from others
  • Aggression
  • Increased injuries
  • Hearing loss
  • Getting lost
  • Paranoia
  • Inappropriate behaviors

How Is Dementia Prevented?

Making or maintaining healthy lifestyle habits may help to prevent or delay age-related cognitive decline and senility, according to the National Institute on Aging (NIA).

One of the most important things you can do is to maintain healthy blood pressure. Hypertension can be managed through diet, exercise, and medication.

Get Regular Exercise

Exercise not only helps lower blood pressure, but it may also reduce your risk of dementia and help slow cognitive decline.

Research shows that regular aerobic exercise, like brisk walking, helps improve executive function skills (the ability to plan and organize) in older adults.

Exercise is also recommended for people who have already been diagnosed with dementia. While the research is not as strong, studies suggest it may still provide cognitive benefits.

Follow the MIND Diet

Research shows following the MIND diet may help slow age-related cognitive decline. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet combines the heart-healthy Mediterranean diet with the blood-pressure-controlling DASH (Dietary Approaches to Stop Hypertension) diet.

A 2023 study in the journal Neurology found, on autopsy, that those with the highest adherence to the MIND diet principles showed fewer indications of dementia-related brain changes. What's more, their brains also looked about four years younger.

Eating more green leafy vegetables, fatty fish, and legumes was also associated with healthier brains. Not surprisingly, eating a lot of sugary and fried foods was linked to greater evidence of dementia.

Keep Your Brain Active

Research shows cognitive training—structured activities designed to enhance memory, reasoning, and processing speed—can help delay or slow age-related cognitive decline.

Informal activities that keep your mind active can help, too. Studies show reading, playing games, crafting, computer games, and social activities may help lower the risk of cognitive impairment with age.

Additional Prevention Tips

There are a few steps you can take in addition to a healthy lifestyle to help prevent dementia:

  • Always wear a helmet when engaging in sports where a head injury is possible (biking, skiing, etc.).
  • Always wear a seatbelt.
  • Try to maintain social contact with family and friends as you age.
  • Avoid smoking and alcohol.

How Is Dementia Treated?

Mild-to-severe dementia may be treated with medications known as acetylcholinesterase inhibitors. These include:

  • Aricept (donepezil)
  • Exelon (rivastigmine)
  • Namenda (memantine)

When to See a Healthcare Provider

Memory issues tend to become more common as people age. However, persistent memory issues accompanied by mood or functional changes could signal something more serious.

The warning signs of dementia include:

  • Short-term memory problems
  • Changes in mood and personality
  • Difficulty planning or problem-solving
  • Difficulty completing tasks
  • Confusion with time or place
  • Getting lost
  • Difficulty communicating (speaking or writing)
  • Misplacing things
  • Decreased or poor judgment
  • Apathy or withdrawal from work or social activities

If you or a loved one have symptoms severe enough to interfere with daily life, it's a good idea to schedule an appointment with a healthcare provider.

Summary

In popular language, the terms "senility" and "dementia" often share the same space. But, in truth, using the word "senility" reinforces the stigma of dementia and no longer has a place in the modern vocabulary.

A progressive decline in a person's ability to think and remember can be due to a wide range of brain conditions. Alzheimer's disease, vascular dementia, Lewy body dementia, and frontotemporal dementia are the more common causes of dementia. 

Research suggests following a healthy lifestyle, including getting regular exercise and following the MIND diet, may help prevent or delay dementia. Keeping your mind active with cognitive training and everyday activities can also help to slow cognitive decline.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. U.S. National Library of Medicine: MedlinePlus. Neurocognitive disorder.

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  11. AARP. 10 Early Warning Signs of Dementia You Shouldn’t Ignore.

Additional Reading
  • American Psychiatric Association. (2013) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, Virginia: American Psychiatric Association.

By Esther Heerema, MSW
Esther Heerema, MSW, shares practical tips gained from working with hundreds of people whose lives are touched by Alzheimer's disease and other kinds of dementia.