A disease of the joints, osteoarthritis affects more than 30 million adults and is the fifth-leading cause of disability in the United States. In a new study, scientists have discovered the cellular pathway that leads to osteoarthritis and have identified a commonly used anti-depressant—paroxetine—that inhibits this pathway. The team found that Paroxetine not only slows down cartilage degeneration, but also promotes cartilage health in both mice and human cartilage in vitro. The drug may be the first-ever treatment for this debilitating, degenerative disease.