The development of new drugs has contributed to reducing the physical and financial burden on patients and the labor required to care for them by their families, thereby reducing medical costs. For example, a drug developed in the 1990s to slow the progression of Alzheimer's disease (a disease that causes memory loss and memory impairment due to a decrease in the number of nerve cells that make up the brain) has reduced the amount of work and expense required for family members to care for patients.