Adolescence is the period from 10 to 11 years old to 14-15 years old. For most students, the transition to adolescence usually begins in the 5th grade. "A teenager is no longer a child, but not an adult either" - this definition indicates the important character of adolescence. At this age, drastic changes in adolescent development begin to occur. This brochure describes the specific characteristics of mental development during adolescence.