Adolescent medicine also known as adolescent and young adult medicine is a medical subspecialty that focuses on care of patients who are in the adolescent period of development. This period begins at puberty and lasts until growth has stopped, at which time adulthood begins. Typically, patients in this age range will be in the last years of middle school up until college graduation (some doctors in this subspecialty treat young adults attending college at area clinics, in the subfield of college health). In developed nations, the psychosocial period of adolescence is extended both by an earlier start, as the onset of puberty begins earlier, and a later end, as patients require more years of education or training before they reach economic independence from their parents.