Background and Adolescent Morbidity

Whereas congenital anomalies and malignant neoplasms are the leading causes of death in childhood, high-risk behaviors manifest during adolescence and place the individual at risk for related morbidities and even mortality.^1,2 In the United States, unintentional injury, homicide, and suicide are leading causes of death among 15- to 19-year-olds. Seventy-one percent of all deaths among persons 10 to 24 years of age result from four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide.² The 2005 Youth Risk Behavior Survey conducted by the Centers for Disease Control and Prevention showed that 10% of high school students had driven a car or other vehicle when they had been drinking alcohol, and close to 20% had carried a weapon. Thirty-six percent of high school students had been in a physical fight during the 12 months preceding the survey, and 8% had attempted suicide.

Psychosocial Problems

Nearly 50% of those surveyed admitted to having had sexual intercourse, and 37% did not use a condom during their most recent sexual intercourse. Half of respondents admitted to drinking alcohol frequently, 20% had used marijuana, and 2% had injected illegal drugs. Feeling sad or hopeless is also common among adolescents. The survey found that during the preceding 12 months, 28.5% of the teens surveyed had felt so sad or hopeless almost every day for 2 or more weeks in a row that they stopped doing some usual activities.² Another study found that 4.6% of those 13 to 17 years of age were taking medications to treat attention-deficit/hyperactivity disorder (ADHD), with 16-year-old males having the highest prevalence of 14.9%.³

The two major causes of death in adults, cardiovascular disease and cancer, may in fact have their origins in adolescence, and possibly childhood. During 2005, 25% of high school students had admitted to smoking cigarettes during the 30 days preceding the Youth Risk Behavior Survey. Sixty-seven percent did not attend regular physical education classes, and 13% were overweight.²

Phases of Adolescence

Adolescence, a period of tremendous physical growth, is divided into three phases: early (11 to 14 years), middle (15 to 17 years), and late adolescence (18 to 21 years). Weight gain during puberty accounts for about 50% of ideal adult weight, and linear growth during puberty accounts for 20% to 25% of adult height. Up to two-thirds of adult bone mass is accrued during this period. It is also a time of marked divergence in the physical features and body habitus of females versus males that goes beyond gonadal and breast development. Female body fat increases from about 16% to about 27%. When puberty is complete, males have 50% more lean body mass than women, and women have twice the body fat of men. Ninety-five percent of females complete growth by age 16, whereas 95% of males complete growth by age 18.⁴

Menarche occurs and pubertal development goes through predictable stages as outlined in Table 24-1 for girls and Table 24-2 for boys and Figures 24-1 and 24-2.

Table 24-1 Classification of Sexual Maturity Stages in Girls

Table 24-2 Classification of Sexual Maturity Stages in Boys