Table 1 Diagnostic and Statistical Manual (DSM-IV) criteria for delirium1
ADisturbance of consciousness (ie, reduced clarity of awareness of the environment) with reduced ability to focus, sustain or shift attention.
BA change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established or evolving dementia.
CThe disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
DDSM-IV distinguishes between delirium due to general medical conditions, substances (intoxication or withdrawal), multiple aetiologies and others. Thus D criterion varies with aetiology.