Recent investigations, both within and outside of the ICU, have moved beyond simply assigning patients the dichotomous outcome of either being delirious or not, and instead focused on grading the severity of delirium. (19, 20) Patients who have some of the characteristics of delirium, but not full clinical delirium, are deemed to have subsyndromal delirium.[10] The ICDSC, given that its 8 different domains have each been shown to have good item reliability towards the diagnosis of delirium, allows one to identify those ICU patients that fall short of the threshold diagnostic criteria for overt or 'clinical delirium' but who still may have clinically important sub-syndromal delirium (ie. an ICDSC of 1-3). (19)