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Diagnosis of delirium and confusional states

Joseph Francis, Jr, MD, MPH
G Bryan Young, MD, FRCPC
Section Editors
Michael J Aminoff, MD, DSc
Kenneth E Schmader, MD
Deputy Editor
Janet L Wilterdink, MD


Delirium and confusional states are among the most common mental disorders encountered in patients with medical illness, particularly among those who are older. They are associated with many complex underlying medical conditions and can be hard to recognize. Systematic studies and clinical trials are difficult to perform in patients with cognitive impairment. Recommendations for evaluating and treating delirium are based primarily upon clinical observation and expert opinion [1].

Knowledge of the clinical epidemiology of delirium and confusional states in various settings has substantially increased as a result of applying standardized diagnostic methods. These prospective observational studies provide a basis for understanding and managing the disorder.

The epidemiology, pathogenesis, clinical features, and diagnosis of delirium and confusional states will be reviewed here. The prevention and treatment of these disorders are discussed separately. (See "Delirium and acute confusional states: Prevention, treatment, and prognosis".)


The American Psychiatric Association's Diagnostic and Statistical Manual, 5th edition (DSM-V) lists five key features that characterize delirium [2]:

Disturbance in attention (reduced ability to direct, focus, sustain, and shift attention) and awareness.

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Literature review current through: Sep 2017. | This topic last updated: Aug 22, 2014.
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