Dementia and Alzheimer’s: What’s the Difference?

Reviewed by: HU Medical Review Board | Last reviewed: January 2023

The terms dementia and Alzheimer’s are often used together. This can lead to the idea that the 2 terms mean the exact same thing, or that they describe the same disease. But this is not the case.1-3

Alzheimer’s is a type of dementia. But not all dementia is caused by Alzheimer’s. Understanding the difference and related terms may allow you to more accurately describe symptoms. The better you can describe to your doctor what is happening, the easier it will be for them to decide how best to help.2

Dementia definition

Dementia is a broad term. It describes a group of cognitive or “thinking” symptoms that can include a decline in reasoning, memory, language, and other thinking skills. There are many different types of dementia. And it can be caused by a variety of conditions and diseases. Sometimes, it is caused by more than one thing at a time – a condition called “mixed dementia.”1-3

While you may become a little more forgetful or have some mild difficulty thinking as you get older, dementia is not a normal part of life as you age. Dementia describes cognitive symptoms that are severe enough that they significantly impact daily life and functioning.1-3

All dementia is caused by some kind of damage to neurons, the cells in your brain that send signals to allow you to reason, think, and move. Damage to your neurons can cause communication issues, memory loss, behavioral changes, and emotional changes, among other symptoms.1

Common symptoms of dementia include:2,3

  • Trouble remembering things
  • Poor judgment or reasoning skills
  • Decreased focus and attention
  • Changes in behavior
  • Difficulty with language

There are many different kinds of dementia, including:2

  • Alzheimer’s disease
  • Lewy body dementia
  • Frontotemporal dementia
  • Vascular dementia
  • Other, rarer forms of dementia including Creutzfeldt-Jakob disease and Huntington’s

Each different cause of dementia may affect different areas of the brain more than others, leading to a different pattern of cognitive symptoms.1,2

Definition of Alzheimer’s disease

Alzheimer’s disease is the most common cause of dementia. Alzheimer's is the reason behind about 60 to 80 percent of cases of dementia. Alzheimer’s is a brain disease that results in damage to neurons. Harmful proteins cause this damage by collecting inside and outside of the neurons. This damage leads to the symptoms of Alzheimer’s.1,2

Alzheimer’s is marked by symptoms of dementia that get worse over time. It is normally diagnosed around age 65, though onset can be earlier in some cases. Symptoms include:1,4

  • Trouble with memory and reasoning
  • Disorientation and confusion
  • Behavioral changes
  • Difficulty speaking, swallowing, and walking

Alzheimer’s is progressive. This means symptoms will develop and worsen over time, typically over several years. There are 3 stages to Alzheimer’s: early, middle, and late. These involve different levels of symptoms. The person with Alzheimer's will need more and more help as the stages progress.4

Differences between Alzheimer’s and dementia

Dementia is a more general term for mental decline that is severe enough to impact daily life and functioning. Alzheimer’s, on the other hand, is a specific disease that causes dementia. A person can have Alzheimer’s without having all of the symptoms that fall under the term of dementia.1,3

Dementia is not a disease in itself. Instead, it is a broad term used to refer to significant cognitive difficulties in one or more areas of thinking, regardless of their underlying cause. Because of this, it can occur for a variety of reasons. Depending on the underlying cause, dementia may or may not have a specific progression.3,4

Alzheimer’s is a progressive and irreversible disease. There are ways to slow the progression or ease symptoms, but there is currently no cure.3

Though many types of dementia (including Alzheimer’s) are irreversible, there are exceptions. Dementia can be caused by vitamin deficiency, underactive thyroid, depression, or stress. In these cases, treating the underlying issue can cure the dementia.3

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