Teenagers experience physical, cognitive, social and emotional changes in the passage to adulthood. Although teenagers view themselves as grown up, they have yet to make the dramatic changes necessary to become mature adults. While much growth occurs, the teenage years do not have to be a tumultuous time.
Adolescents experience significant physical growth during their teenage years, typically from the ages of 13 to 19. According to the website, Blackwell Publishing, girls gain on average about 20 pounds a year while boys gain an average of 24 pounds per year. The body is flooded with hormones. Secondary sexual characteristics develop with genitals growing to adult size and functionality. Boys and girls start getting body hair, and boys get facial hair. Girls' bodies become rounder and more feminine, while boys' bodies become more muscular and masculine.
Child psychologist Jean Piaget documented cognitive changes beginning in adolescence through adulthood. He called this period of cognitive development formal operations. During this time, teenagers experience an intellectual growth spurt, where their thinking becomes more abstract and their problem-solving more systematic. Due to their increased intellectual capacity, teenagers begin to develop very idealistic and sometimes unrealistic views.
Adolescents are more susceptible to peer pressure than at any other age. Because they are developing their own identities, adolescents try on a number of different ways of responding, dressing and thinking, auditioning these before their peers. The process of sifting through various identities seem chaotic to an adult, but it's a normal part of adolescent development. It's also necessary for the adolescent to discover who he is and what he believes.
Teenagers are thought to be extremely moody due to the influx of secondary sex hormones. Many mental illnesses, such as schizophrenia, bipolar disorder and depression, occur for the first time during adolescence. For most teenagers these years are not fraught with emotional turmoil. Signs that a teenager is experiencing emotional difficulty include sleeping problems, withdrawal, talking about self-harm and sustained changes in regular routines.