Traditionally, delirium has been regarded as a transient disorder that terminates with either recovery or death. In the majority of cases, the delirious episode is relatively short, but about one-third of patients have prolonged or recurrent episodes. Delirium is associated with increased short-term mortality in elderly patients, due mainly to the underlying physical illness. However, delirious patients also tend to have longer hospital stays, higher rates of functional decline, and higher rates of discharge to nursing homes. Other complications of delirium include falls and fractures if the patient is hyperactive, and pressure sores if they are hypoactive. Prospective studies show that the prognosis in terms of persistent or recurrent symptoms of delirium is relatively poor in elderly patients. This is probably because those who experience delirium are a vulnerable group more likely to develop the condition whenever they become physically ill. A proportion will also be suffering from a form of dementia, which will increase their vulnerability to delirium as it progresses. It is not known if delirium is itself a risk factor for the development or exacerbation of dementia. The family and other carers should be advised of the risk of future delirium, and educated about the symptoms so that they can recognize it if and when it occurs again.