Mental confusion, also called delirium, is a change in a person’s awareness. Confusion affects how a person thinks, sees the world around them, and remembers things.

The main signs of mental confusion or delirium are sudden changes in awareness. A person with confusion or delirium might suddenly get very sleepy and unaware of their surroundings or act very upset and nervous. The person will not recognize this change in themselves and is most often noted by family members or medical providers.

Appetite loss or poor appetite are common side effects from cancer and its treatment. This means that you may eat less than usual, not feel hungry at all, or feel full after eating only a small amount.

Ongoing appetite loss may lead to serious complications. These include weight loss, not getting the nutrients that the body needs, and fatigue and weakness from muscle loss, which is called cachexia (see below). These issues can slow recovery and lead to breaks in treatment.