A. Disturbance of consciousness (eg, reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.

B. A 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 preexisting, established, or evolving dementia.

C. The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.

Individual criteria (D) for each of the three conditions are as follows:

General Medical Condition
D. There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiologic consequences of a general medical condition.

Substance Intoxication
D. There is evidence from the history, physical examination, or laboratory findings of either (1) or (2)
1. The symptoms described in criteria A and B developed during Substance Intoxication.
2. Medication use is etiologically related to the disturbance.

Multiple Etiologies
D. There is evidence from the history, physical examination, or laboratory findings that the delirium has more than one etiology (eg, more than one etiologic general medical condition, a general medical condition plus substance intoxication or medication side effect).