"Delirium needs treatment for both its causes and manifestations, as, if ignored, it is associated with excessive periods of hospitalisation or early mortality. The common causes include infection, drug intoxication, renal or hepatic insufficiency, vascular disease affecting the brain, and (often forgotten) electrolyte disturbance. The main interventions are environmental and pharmacological and the symptoms on which they are focused are agitation, over-activity, restlessness and other behavioural disturbance, and psychotic symptoms such as hallucinations, delusions and paranoid reconstruction of the world. As might be expected, randomised controlled trials are very difficult to carry out in this population as its manifestations are acute and cannot be ignored, and most of the evidence of efficacy of interventions is based on less convincing models"--Provided by publisher.