The 3 D's: Delirium vs Dementia vs Depression — Acute vs Chronic vs Treatable
An 80-year-old is confused and withdrawn — is it delirium, dementia, or depression? Each demands a completely different response. Choosing wrong means missing a life-threatening infection in delirium, withholding antidepressants in depression, or futilely trying to "cure" dementia.
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- ★Acute (hrs–days)
- fluctuates, worse at night
- Insidious (months–years)
- steady decline
- Variable (weeks–months)
- mood-driven
- Clouded consciousness
- impaired attention
- Visual hallucinations
- reversed sleep-wake
- ★Recent memory lost first
- remote preserved
- Consciousness clear until late
- ★'I don't know' answers
- recalls with cues
- Sad mood, anhedonia
- early-morning waking
- Reversible with treatment
- ★Find cause: UTI, meds, hypoxia
- Irreversible, progressive
- Reversible with treatment
- Screen with GDS / PHQ-9
- Correct underlying cause
- reorient
- avoid restraints
- Maintain routine
- support ADLs
- Simple one-step cues
- Screen suicidality
- promote socialization
- Treat cause
- minimize sedatives
- Donepezil
- memantine
- SSRIs, therapy
- ECT for severe
- Often resolves with treatment
- expect fluctuation
- Safety-proof home
- caregiver respite
- Meds take 2–4 weeks to work
- watch for suicidality
- Acute change = emergency
- rule out hypoxia/sepsis
- Sudden decline: suspect delirium
- ★Active suicidal ideation/plan
- ↑ Mortality, longer hospital stay
- Total dependence
- aspiration
- Suicide
- functional decline
Delirium
- ★Acute (hrs–days)
- fluctuates, worse at night
Dementia
- Insidious (months–years)
- steady decline
Delirium
- Clouded consciousness
- impaired attention
- Visual hallucinations
- reversed sleep-wake
Dementia
- ★Recent memory lost first
- remote preserved
- Consciousness clear until late
Delirium
- Reversible with treatment
- ★Find cause: UTI, meds, hypoxia
Dementia
- Irreversible, progressive
Delirium
- Correct underlying cause
- reorient
- avoid restraints
Dementia
- Maintain routine
- support ADLs
- Simple one-step cues
Delirium
- Treat cause
- minimize sedatives
Dementia
- Donepezil
- memantine
Delirium
- Often resolves with treatment
- expect fluctuation
Dementia
- Safety-proof home
- caregiver respite
Delirium
- Acute change = emergency
- rule out hypoxia/sepsis
Dementia
- Sudden decline: suspect delirium
Delirium
- ↑ Mortality, longer hospital stay
Dementia
- Total dependence
- aspiration
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Delirium is acute and reversible — treat it. Dementia is gradual and irreversible — manage it. Depression is treatable — screen for it.
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