Confusion Assessment Method (CAM)

Bedside diagnostic algorithm for delirium
Acute onset or a fluctuating course (Feature 1)
Inattention (Feature 2)
Disorganised thinking (Feature 3)
Altered level of consciousness (Feature 4)
Evidence
Original publication
Inouye SK, van Dyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Derived and validated the four-feature diagnostic algorithm used here against a psychiatrist’s DSM-III-R diagnosis (sensitivity 94–100%, specificity 90–95% across two sites).
Annals of Internal Medicine, 1990
Open source
Guideline
CAM is a diagnostic algorithm, not a screen you can use untrained — accurate use assumes the rater has assessed attention and the other features with a brief bedside cognitive test (e.g. counting backward from 20, reciting the months backward) and knows the patient’s cognitive baseline. It does not grade delirium severity; a positive CAM prompts a search for and treatment of the underlying cause(s).
Last reviewed: 2026-09
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