Screening, Assessment, and Intervention by Adolescent stage.
One simple way to understand adolescence is to divide it into three psychosocial developmental phases: early, 11 to 14 years or junior high school; middle, 15 to 17 years or high school; and late, 18 to 21 years or college, work, or vocational technical school.
Each phase is characterized by certain behaviors. Understanding these behaviors can assist in identifying behaviors of concern to the adolescent or family. Within each developmental phase, adolescents deal with issues of autonomy, body image, peer group involvement, and identity development.