What is delirium?

Delirium is a serious disturbance in mental abilities that results in confused thinking and a reduced awareness of the environment. Delirium can happen suddenly over one or two days and the person may feel drowsy and sleepy. It can be caused by many different things, including the presence of an infection (such as of the bladder and urinary tract) or following a head injury. It can occur in anybody but is more common in people suffering from dementia.