What Does "Senile" Really Mean? Is It the Same as Dementia?

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Definition of Senile: Short Answer

The most basic definition of senile is "relating to, exhibiting, or characteristic of, old age" (Merriam-Webster).

However, the use of the word senile is more commonly associated with a decline in mental abilities such as memory loss or confusion as people age.

Other Forms and Contexts of Senile

Senile is often combined with other words including senile Alzheimer's, senile dementia and senile plaques.

Another form of the word is senility.)

More about the Word Senile

The word senile loosely references the loss of cognitive abilities or the inability to think clearly. 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."  

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 was 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 developed in older age.

Science now understands that significant memory loss, disorientation and confusion are NOT normal parts of aging but rather are symptoms of a neurocognitive disorder such as Alzheimer's, vascular dementia, frontotemporal dementia, or Lewy body dementia.

While senile is not used any longer in the medical field as a diagnosis or descriptor, it is sometimes used to describe the plaques that build up in the brain as Alzheimer's disease progresses. These plaques are often described as one of the hallmarks of Alzheimer's disease, along with neurofibrillary tangles.

What Is SDAT (Senile Dementia- 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 and had developed after the age of 65. 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 neurocgonitive disorder due to Alzheimer's disease.  

More about (Senile) Dementia

While describing someone as "senile" is not medically accurate and has a negative connotation, the concept of senility is comparable to that of dementia.

You can work to reduce your risk of dementia (senility) by eating brain-healthy foodsexercising regularly and staying active mentally. Even after dementia has developed, these strategies may be able to slow the progression of the disease to some extent.


Alzheimer's Aid Society of Northern California. Senile Dementia. http://alzaid.org/SenileDementia.html

Alzheimer's Society. Senile Dementia. http://www.alzheimers.org.uk/site/scripts/services_info.php?serviceID=165

DSM-5.org. Updates to neurocognitive disorders in DSM5 and DSM5 Desk Reference. October 18, 2013. http://www.dsm5.org/Documents/IMPORTANT-NeurocogCodingNoteUpdates-10-18-13.pdf

Merriam-Webster Dictionary. Senile. http://www.merriam-webster.com/dictionary/senile

University of Maryland Medical Center. Alzheimer's Disease. http://umm.edu/health/medical/ency/articles/alzheimers-disease

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