Differences Between Delirium and Dementia*
Feature | Delirium | Dementia |
|---|---|---|
Onset | Sudden, with a definite beginning point | Slow and gradual, with an uncertain beginning point |
Duration | Days to weeks, although it may be longer | Usually permanent |
Cause | Almost always another condition (eg, infection, dehydration, use or withdrawal of certain medications) | Usually a chronic brain disorder (eg, Alzheimer disease, dementia with Lewy bodies, vascular dementia) |
Course | Usually reversible | Slowly progressive |
Effect at night | Almost always worse | Often worse |
Attention | Greatly impaired | Unimpaired until dementia has become severe |
Level of consciousness | Variably impaired | Unimpaired until dementia has become severe |
Orientation to time and place | Varies | Impaired |
Use of language | Slow, often incoherent, and inappropriate | Sometimes difficulty finding the right word |
Memory | Varies | Lost, especially for recent events |
Need for medical attention | Immediate | Required but less urgently |
Effect of treatment | Usually reverses symptoms | May slow progression but cannot reverse or cure the disorder |
* Differences are generally true and helpful diagnostically, but exceptions are not rare. For example, traumatic brain injury occurs suddenly but may result in severe, permanent dementia; hypothyroidism may produce the slowly progressive picture of dementia but be completely reversible with treatment. | ||