multi class comparison

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An 80-year-old is confused and withdrawn — is it delirium, dementia, or depression?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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Comparison

Side-by-side3 compared
Comparevs
Dimension
Delirium
Dementia
Depression
Onset & course
  • ★Acute (hrs–days)
  • fluctuates, worse at night
  • Insidious (months–years)
  • steady decline
  • Variable (weeks–months)
  • mood-driven
Signs & symptoms
  • 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
  • Apathy
  • early-morning waking
Reversibility / workup
  • ★REVERSIBLE — find cause (UTI, meds, hypoxia)
  • Irreversible, progressive
  • Reversible
  • screen PHQ-9 / GDS
Priority care
  • Correct underlying cause
  • reorient
  • avoid restraints
  • Maintain routine
  • support ADLs
  • reduce stimuli
  • Screen suicidality
  • promote socialization
Treatment & meds
  • Treat cause
  • minimize sedatives
  • Donepezil
  • memantine
  • SSRIs, therapy
  • ECT for severe
Family / caregiver
  • Often resolves with treatment
  • expect fluctuation
  • Safety-proof home
  • caregiver respite
  • Meds take weeks
  • watch for suicidality
Red flags — escalate
  • Acute change = emergency
  • rule out hypoxia/sepsis
  • Rapid decline then assess superimposed delirium
  • ★Active suicidal ideation/plan
Complications
  • Untreated then death, prolonged stay
  • Total dependence
  • aspiration
  • Suicide
  • functional decline
Onset & course

Delirium

  • ★Acute (hrs–days)
  • fluctuates, worse at night

Dementia

  • Insidious (months–years)
  • steady decline
Signs & symptoms

Delirium

  • Clouded consciousness
  • impaired attention
  • Visual hallucinations
  • reversed sleep-wake

Dementia

  • ★Recent memory lost first
  • remote preserved
  • Consciousness clear until late
Reversibility / workup

Delirium

  • ★REVERSIBLE — find cause (UTI, meds, hypoxia)

Dementia

  • Irreversible, progressive
Priority care

Delirium

  • Correct underlying cause
  • reorient
  • avoid restraints

Dementia

  • Maintain routine
  • support ADLs
  • reduce stimuli
Treatment & meds

Delirium

  • Treat cause
  • minimize sedatives

Dementia

  • Donepezil
  • memantine
Family / caregiver

Delirium

  • Often resolves with treatment
  • expect fluctuation

Dementia

  • Safety-proof home
  • caregiver respite
Red flags — escalate

Delirium

  • Acute change = emergency
  • rule out hypoxia/sepsis

Dementia

  • Rapid decline then assess superimposed delirium
Complications

Delirium

  • Untreated then death, prolonged stay

Dementia

  • Total dependence
  • aspiration

★ marks the fact that sets a column apart.

Clinical Pearl

Delirium is acute and reversible — treat it. Dementia is gradual and irreversible — manage it. Depression is treatable — screen for it.

Component Topics

Delirium vs Dementia vs Depression — The 3 D's

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