A medical setback, also known as a RELAPSE, is a return of a medical condition after a period of improvement or remission. It can occur in any medical condition, but is most commonly associated with chronic illnesses such as cancer, HIV/AIDS, and multiple sclerosis. A RELAPSE can be caused by a variety of factors, including changes in lifestyle, stress, or the development of new symptoms. Treatment for a medical setback may involve medications, lifestyle changes, or other therapies.