The current therapeutic agents advocated for the treatment of delirium (Meagher, 2001) have not been developed from an understanding of the underlying pathophysiology of this condition. Rather, they have emerged from “off label” clinical practice which has sought to reduce the distress experienced by both patients and clinicians. Accordingly, their use has not developed from a strong, specific evidence base, and nor is it now supported by large, well-designed clinical trials. It is also the case that these drug treatments will address the management (usually by sedation) of patients with florid, psychotic or “positive” delirium whilst quiet or “negative” delirium remains under-diagnosed and is poorly managed despite the distress it causes patients.