Table 3.

Distinguishing features between delirium, dementia, and psychosis.

Characteristic	Delirium	Dementia	Psychosis
Onset	Acute	Gradual	Variable
Course	Fluctuating	Progressive*	Chronic
Diminished level of consciousness	May be present (hypoactive/mixed delirium)	Absent	Absent
Orientation	Fluctuating	Impaired	Normal
Duration	Hours to months	Months to years	Months to years
Hallucinations	Common	Rare until end stage	Common
Attention	Impaired	Preserved until end stage	May be impaired
Sleep-wake pattern	Disrupted	Normal or fragmented	Variable

^*Exception: fluctuations in cognition are present in Lewy body dementia.²³