Description: Most teens and adults with autism have less severe symptoms and behaviors as they get older, a groundbreaking study shows. Not every adult with autism gets better. Some -- especially those with mental retardation -- may get worse. Many remain stable. But even with severe autism, most teens and adults see improvement over time, find Paul T. Shattuck, PhD, Marsha Mailick Seltzer, PhD, and colleagues at the University of Wisconsin.