There sure is! Some psychologists specialize in studying child and adolescent behavior. Some also specialize in treating children and adolescents who are struggling for one reason or another. .
Yes. There are psychologists that specialize in teens.
Adolescent Psych. Sure there is!
Yes. One of my specialties is working with teens and I teach a course in it as well. Teens have unique developmental challenges that adults and children don't face.
Yes. Child and adolescent psychology is a subfield of clinical psychology that is vibrant, alive, and well. In fact there is board certification in child and adolescent psychology by the American Board of Professional Psychology (ABPP).