Adolescence is the transition from childhood to adulthood, commonly described as early (about 11–14 years), middle (15–17 years), and late (18–21 years) adolescence. It brings rapid physical change (puberty), new thinking abilities, the search for identity, and increasing independence. Most adolescents are healthy; the major threats are behavioral — injuries, violence, suicide, substance use, and sexual health risks.

Puberty begins when the hypothalamus increases gonadotropin-releasing hormone, raising luteinizing and follicle-stimulating hormones, which stimulate the ovaries (estrogen) or testes (testosterone); adrenal androgens add pubic and axillary hair and body odor.

Sex steroids and growth hormone together drive the growth spurt; estrogen in both sexes eventually closes the growth plates, so linear growth stops in late adolescence. Adolescence is also the peak time for building bone mass — girls reach peak bone accrual earlier than boys.

Sexual maturity rating (Tanner stages 1–5) rates breast and pubic hair development in girls and genital and pubic hair development in boys; stage 1 is prepubertal, stage 5 adult. It evaluates whether biologic maturation is proceeding normally and on time — it does not measure behavior, intelligence, or sexual orientation.

Cognitive (Piaget — formal operational, about 11 years and older)

• Abstract and hypothetical-deductive reasoning; considers several variables at once; thinks about the future, possibilities, ideals, and values
• Moves from black-and-white thinking toward seeing complexity in later adolescence
• Adolescent egocentrism:
  • Imaginary audience — feels constantly watched and judged by others → intense self-consciousness about appearance and behavior
  • Personal fable — believes their experiences are unique ("no one understands me") and that they are invulnerable ("it won't happen to me") → risk-taking
• The prefrontal cortex (planning, impulse control) matures into the mid-20s, while reward-seeking is strong — especially in the presence of peers

Psychosocial

• Erikson: identity vs. role confusion — "Who am I?" Exploring roles, values, relationships, and career
• Marcia's identity statuses: diffusion (no exploration, no commitment), foreclosure (commitment without exploration, often adopting parents' choices), moratorium (active exploration, no commitment yet — a healthy stage), achievement (commitment after exploration)
• Peer group is central; conformity is strongest in early to middle adolescence; conflict with parents over independence is common
• Body image is sensitive; self-esteem depends on appearance, peer acceptance, achievement, and family support
• Moral development: conventional reasoning (law and order); some reach postconventional reasoning (social contract, universal principles) in late adolescence or adulthood
• Sexual identity and romantic relationships develop

• BMI-for-age percentiles, blood pressure, Tanner stage, and height velocity at yearly visits
• Confidential psychosocial interview (HEEADSSS): Home, Education/employment, Eating, Activities, Drugs, Sexuality, Suicide/depression, Safety (including violence, bullying, driving, online safety)
• Depression screening yearly from 12 years (e.g., PHQ-A); suicide risk screening when indicated; anxiety screening
• Substance use screening (e.g., CRAFFT) for alcohol, cannabis, nicotine and vaping, and other drugs
• Sexually active adolescents: chlamydia and gonorrhea screening (at least yearly for sexually active females), HIV testing at least once, pregnancy testing as indicated
• Lipid screening once between 17 and 21 years (US); vision and hearing per schedule; scoliosis per local policy

Management centers on preventive care, confidential services, and treating common adolescent conditions.

Immunizations — adolescent doses of Tdap/Td, HPV, and meningococcal vaccines (US: Tdap, HPV, and MenACWY at 11–12 years; MenACWY booster at 16; HPV 2 doses if started at 9–14, or 3 doses if started at 15 or older or immunocompromised), plus annual influenza where recommended; check the current national schedule (see Immunizations)

Nutrition

• High needs for energy, protein, calcium (about 1,300 mg/day for ages 9–18), vitamin D, and iron (increased by menstruation in girls and muscle growth in boys)
• Frequent snacking, skipped breakfast, fast food, and sugary or energy drinks are common; avoid restrictive dieting

Sleep: about 8–10 hours per night; the circadian rhythm shifts later ("night owl"), so early school start times cause chronic sleep deprivation

Common drug-related points

• Acne: topical benzoyl peroxide (skin dryness, bleaches fabric) and retinoids (irritation, sun sensitivity); oral tetracyclines such as doxycycline (photosensitivity, esophageal irritation — take with water and stay upright; avoid in pregnancy); isotretinoin for severe acne is highly teratogenic — requires pregnancy prevention with two forms of contraception and monthly pregnancy tests in the US (iPLEDGE), and monitoring of mood (depression, suicidal thoughts), lipids, and liver enzymes. Do not combine isotretinoin with tetracyclines (pseudotumor cerebri — headache, vision changes); avoid vitamin A supplements; no blood donation during and for 1 month after treatment
• Contraception: long-acting reversible methods (implant, IUD) are first-line options for adolescents; combined estrogen–progestin methods increase venous thromboembolism risk and are contraindicated in migraine with aura; condoms for STI protection with any method
• Sports: supervised strength training with proper technique; avoid anabolic steroids and unregulated supplements

Listed in priority order.

1. Assess safety and suicide risk directly — ask about suicidal thoughts in plain words; asking does not increase risk. Any adolescent who mentions suicide is asking for help; do not leave alone if at imminent risk, remove means (firearms, medications), and escalate
2. Recognize risk behaviors linked to the personal fable: driving (seat belts, no texting, no impaired driving), substance use, unprotected sex, dangerous online challenges; use motivational, non-judgmental counseling
3. Confidentiality: interview the adolescent alone for part of every visit; explain that information stays private unless there is a risk of serious harm to self or others or abuse must be reported
4. Therapeutic communication: open-ended questions ("Can you tell me what makes you think that?"), active listening, respect; avoid lecturing, false reassurance ("Don't worry, everyone likes you"), or dismissing feelings
5. Hospitalized adolescent
   • Main concerns: loss of privacy and independence, body image changes, separation from peers, falling behind in school
   • Explain the reasons, principles, and long-term effects of treatment — adolescents can think abstractly
   • Involve them in decisions and care planning; allow peer contact and personal items; protect privacy during examinations
6. Support self-management of chronic illness: teach disease mechanisms and treatment rationale so the adolescent can make decisions; gradually shift responsibility from parents; plan transition to adult care
7. Support identity and self-esteem: encourage exploration of interests; recognize strengths; screen for bullying and dating violence
8. Health education on puberty, menstruation, sexual health, contraception, nutrition, sleep, and mental health

• Adolescents: body changes happen at different times — being earlier or later than friends is usually normal; breast asymmetry during development is common; menstrual cycles are often irregular for the first 1–2 years after menarche
• Protect bones: calcium- and vitamin D-rich foods, weight-bearing activity
• Protect sleep: consistent schedule, screens off before bed
• Avoid tobacco, vaping, alcohol, and drugs; never ride with an impaired driver
• Parents: respect privacy, support independent decisions, encourage exploration of interests and careers, keep communication open, and stay involved; do not impose parental values rigidly or isolate the teen from peers; keep firearms and medications locked
• Know the crisis line numbers (see Country Notes)

• Depression: in adolescents often shows as irritability, anger, falling grades, withdrawal from friends and family, sleep and appetite changes, somatic complaints — not only sadness
• Suicidal talk, giving away belongings, self-harm (cutting), sudden calm after depression — urgent evaluation. Adolescent girls attempt suicide more often; males die by suicide more often (more lethal methods)
• Eating disorders: fear of weight gain, distorted body image (seeing oneself as fat at normal or low weight), amenorrhea, bradycardia, hypotension, electrolyte abnormalities, lanugo
• Substance use, risky sexual behavior, dating violence, sexual exploitation
• Delayed puberty (no breast development by 13 years in girls, no testicular enlargement by 14 years in boys) or primary amenorrhea (no menarche by 15 years, or 3 years after thelarche); precocious puberty (before 8 in girls, 9 in boys)
• Rapidly progressive scoliosis during the growth spurt

• First sign of puberty: girls — breast budding; boys — testicular enlargement
• Menarche about 2–2.5 years after thelarche; early cycles irregular
• Girls' growth spurt about 2 years earlier than boys'; estrogen closes growth plates
• Tanner stages assess biologic maturation (normal progression and timing)
• Identity vs. role confusion; moratorium = exploring without commitment yet
• Formal operations: abstract, hypothetical-deductive thinking → explain principles and long-term consequences
• Imaginary audience = everyone is watching; personal fable = unique and invulnerable → risk-taking
• Adolescent depression often = irritability and school decline
• Always take mention of suicide seriously; ask directly
• Confidential time alone, with limits for safety
• Isotretinoin is teratogenic; tetracyclines cause photosensitivity
• Calcium 1,300 mg/day; sleep 8–10 hours