Delirium is a serious disturbance in a person's mental abilities that results in a decreased awareness of one's environment and confused thinking. The onset of delirium is usually sudden, often within hours or a few days.

Delirium can often be traced to one or more contributing factors, such as a severe or chronic medical illness, medication, infection, surgery, or drug or alcohol abuse.

The symptoms of delirium and dementia can be similar, and input from a family member or caregiver may be important for a doctor to make an accurate diagnosis.

Aug. 15, 2012