The Difference Between Alzheimer’s and Dementia

People at my talks often ask me, “What is the difference between Alzheimer’s and dementia?”

According to the Merriam-Webster Medical Dictionary, “disease” is “an impairment of the normal state of the living animal or plant body or one of its parts that interrupts or modifies the performance of the vital functions, is typically manifested by distinguishing signs and symptoms, and is a response to environmental factors (as malnutrition, industrial hazards, or climate), to specific infective agents (as worms, bacteria, or viruses), to inherent defects of the organism (as genetic anomalies), or to combinations of these factors.”

dementia_womanA disease is physical: “an impairment of the … body or one of its parts.”  If you look at the brain of a person with Alzheimer’s disease after their death, you find plaques on the brain that impair nominal functioning.

Dementia is a symptom of disease.  When the “vital functions” of the brain are modified in such a manner as to cause wandering, hallucinations, or particular other behaviors or cognitive failures called dementia, these are symptoms.

So, a particular disease has a particular physical pathology. “Dementia” has no particular pathology. According to the definition of “disease”, dementia actually falls into the symptom or expression of the disease;  the interrupted or modified “performance of the vital functions … manifested by distinguishing signs and symptoms….”

In other words, dementia is not a disease, but the signs and symptoms of disease. You will not find dementia in an autopsy. This is why we speak of “Alzheimer’s related dementia” or “dementia related to multiple strokes.” The disease is Alzheimer’s in one case and strokes in the other.   The symptom is dementia.



David Lazaroff is author of Live It Up! 10 Ways to Share Joy When Your Friend Has Alzheimer’s.  David coaches family and friends of people with Alzheimer’s Disease in creating a fun and joyful life.  Contact

David is the founder of Holistic Community Living, a Colorado nonprofit founded to operate and teach others to operate neighborhood-based assisted living homes where people can complete their lives with those they love.

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