Table 1 Diagnostic and Statistical Manual of Mental Disorders (revised third edition) diagnostic criteria for delirium [21]

A.

Reduced ability to maintain and shift attention to external stimuli

B.

Disorganized thinking, as indicated by rambling, irrelevant, or

   incoherent speech

C.

At least two of the following:

1. Reduced level of consciousness

2. Perceptual disturbances: misinterpretations, illusions, or

   hallucinations

3. Disturbance of sleep-wake cycle with insomnia or daytime

   sleepiness

4. Increased or decreased psychomotor activity

5. Disorientation to time, place, or person

6. Memory impairment

D.

Abrupt onset of symptoms (hours to days), with daily fluctuation

E.

Either one of the following:

1. Evidence from history, physical examination, or laboratory tests

   of specific organic etiologic factor(s)

2. Exclusion of non-organic mental disorders when no etiologic

   organic factor can be identified