To determine the diagnostic accuracy of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) for the diagnosis of delirium in adult patients in critical care settings.

To explore potential sources of heterogeneity, as well as specific factors that may influence the accuracy of the CAM-ICU, including: characteristics of recruited patients (patients from medical versus surgical ICUs and type of ventilatory assistance); characteristics of delirium (subtype of delirium or duration of symptoms); characteristics of administration (ICU staff member performing the test); and reference standard used, among others.