Cognitive disorders and delirium are conditions in which the patient experiences a confused mental state and changes in behavior.

People who have cognitive disorders or delirium may fall in and out of consciousness and may have problems with the following:

• Attention.
• Thinking.
• Awareness.
• Emotion.
• Memory.
• Muscle control.
• Sleeping and waking.

Delirium occurs frequently in patients with cancer, especially in patients with advanced cancer.

Delirium usually occurs suddenly and the patient's symptoms may come and go during the day. This condition can be treated and is often temporary, even in people with advanced illness. In the last 24 to 48 hours of life, however, delirium may be permanent due to problems such as organ failure.

Glossary Terms

The mental process of thinking, learning, remembering, being aware of surroundings, and using judgment.

A mental state in which a person is confused, disoriented, and not able to think or remember clearly. The person may also be agitated and have hallucinations, and extreme excitement.

In medicine, a disturbance of normal functioning of the mind or body. Disorders may be caused by genetic factors, disease, or trauma.

A part of the body that performs a specific function. For example, the heart is an organ.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.