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Definition
of Delirium
Definitions
and diagnostic criteria for delirium have evolved over the years
as understanding of its pathophysiologic basis has improved. Standardized
diagnostic criteria, such as the Diagnostic and Statistical Manual
of Psychiatric Disorders 4th
edition (DSM-IV) (American Psychiatric Association (APA), 1994)
criteria, allow formal confirmation of the diagnosis of delirium
for research purposes.
DSM-IV
requires the following essential
criteria for a diagnosis of delirium
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| Disturbance
of consciousness (i.e. reduced clarity of awareness
of the environment) with reduced ability to focus, sustain,
or shift attention. |
| Change
in cognition (e.g. memory deficit, disorientation,
language disturbance and perceptual disturbance) that
is not better accounted for by a pre-existing, established,
or evolving dementia. |
| Development
over a short period of time (usually hours
to days) and disturbance tends to fluctuate
during the course of the day. |
| There
is evidence from the history, physical
examination, or laboratory findings that the disturbance
is caused by the direct physiological consequences of
a general medical condition. |
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The DSM-IV classification subdivides
delirium by etiology into delirium due to:
- substance intoxication delirium;
- substance withdrawal delirium;
- delirium due to multiple etiologies;
and
- delirium not otherwise specified.
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