with an answer to a previous question rather  than appropriately shift attention. The indi-
vidual is easily distracted by irrelevant st imuli. The disturbance in awareness is mani-
fested by a reduced orientation to the environment or at times even to oneself.
The disturbance develops over a short period  of time, usually hours to a few days, and
tends to fluctuate during the course of the day, often with worsen ing in the evening and
night when external orienting stimuli decrease  (Criterion B). There is evidence from the
history, physical examination, or laboratory findings that the disturbance is a physiologi-
cal consequence of an underlying medical condition, substance intoxication or with-