Table 1.

Comparison of features of various psychiatric presentations and deliriumaa

DeliriumDementiaManiaDepressionSchizophreniaAnxiety statesPersonality disorder
OnsetAbruptChronicCan be acuteSubacuteInsidiousChronic or acute in context of major stressorChronic with acute exacerbation of symptoms and/or decompensation in context of stressors
DelusionsPersecutory; fleeting, changeable, poorly formed; first-rank symptoms uncommonDelusions can develop, generally late-stage, simple and persecutoryGrandiose, ‘mood congruent’Nihilistic or persecutory ‘mood congruent’Fixed, false system of beliefs with complex logical structure; ‘first-rank symptoms’AbsentAlthough can have ‘overvalued ideas’, true delusions absent
HallucinationsPredominantly visualBoth auditory and visual can occur in later disease (visual common in Lewy body dementia)If present, generally auditory and ‘mood congruent’If present, generally auditory, ‘mood congruent’Auditory hallucination core feature, especially ‘third person’AbsentNot true hallucinations; ‘pseudohallucinations’
Attention and/or working memoryImpairedRelatively normal until advanced stagesDistractible, but attentional impairment less pronounced than deliriumMinimal impairment, although poor motivation can result in poor performance on assessmentRelatively intactIntactIntact
ArousalAbnormal: hypoalert or hyperalertRelatively normalHyperalertMay be hypoalertRelatively normal or mildly hyperalertRelatively normal or hyperalert in panicNormal or mildly hyperalert
OrientationGenerally disorientated to time and often placeDisorientated in advanced casesOrientatedOrientatedOrientatedOrientatedOrientated
Episodic memoryImpairedImpaired, temporal gradient to memory lossRelatively intactSelective or patchy impairment, might complain about memory impairmentRelatively intactIntactIntact
Motor activityIncreased or decreasedVaries, often normalIncreasedGenerally decreasedGenerally fairly normal, although might be apathetic and can be catatonicOften increasedNormal unless acutely agitated
AffectLabile, although might be fearful or seem depressedVariableElevated mood, although might be irritable and labileSustained low moodPerplexedAnxiousAnger
SpeechSlow and/or rapid, incoherentWord finding difficulty but reasonably coherent until late stagePressured, ‘flight of ideas’Slowed, monotonousDisjointed, ‘loosening of association’Relatively normal, might be slightly pressuredNormal
Sleep–wake cycleVery disturbed, cycle can be reversedSome fragmentationReduced sleep without sleepinessDisturbed, often early-morning wakeningRelatively normal, although sleep-phase disorders common (especially delayed)Initial insomnia characteristicRelatively normal
CourseFluctuating, lucid intervals can misleadStable from day to dayAlternate between elation and irritabilityDiurnal variation in mood, worst in morningStable once established with deterioration generally consequent to medication non-complianceStable with potential episodes of panicStable
  • aLewy body dementia poses particular difficulties in distinguishing from delirium given that visual hallucinations are prominent, the course is fluctuating and consciousness can be impaired.