dementia vs delirium vs depression

Clinical manifestations

• onset
  • dementia: insidious
  • delirium: acute or subacute
  • depression: variable, often abrupt
• duration
  • dementia: chronic, progressive, months to years
  • delirium: hours-days, up to one month
  • depression: week to months to years
• fluctuations
  • dementia: constant, irreversible
  • delirium: abnormal day-night cycle, reversible with treatment
  • depression: reversible with treatment
• kineses
  • dementia: normal to lethargy
  • delirium: abnormal movement, lethargy to agitated
  • depression: normal to lethargy
• attention
  • dementia: shortened attention span
  • delirium: impaired, fluctuating attention span
  • depression: attention span normal, but easily distracted
• arousal
  • dementia: normal
  • delirium: disturbed arousal, (clouding of consciousness)
  • depression: sensorium is clear
• memory
  • dementia: abnormal
  • delirium: impaired recent & immediate memory
  • depression: selective memory impairment
• speech/language
  • dementia: anomic or worse
  • delirium: dysarthric/misnaming
  • depression: normal
• speech content
  • dementia: empty or sparse
  • delirium: confused (incoherent)
  • depression: sad or empty
• cognition:
  • dementia: difficulty with abstraction, problems, word finding; confabulation
  • delirium: thinking is disorganized, distorted
  • depression: intact thinking, but expresses hopelessness or helplessness
• perceptual
  • dementia: normal to moderately abnomal
  • delirium: prominently abnormal (clouded sensorium)
  • depression: normal
• hallucinations:
  • dementia: uncommon
  • delirium: visual > auditory
  • depression: no
• EEG
  • dementia: normal to moderately slow
  • delirium: diffusely slow
  • depression: normal

Additional terms

• delirium (acute confusional state)
• dementia; Alzheimer's disease & related dementias (ADRD)