Adolescence is a developmental stage, occurring from age 11 to 21, which marks a child’s transition to young adulthood. It is generally a time of self-discovery in which young people aim to define their place in the world.

During adolescent development, children complete puberty and physical growth. They also develop important social, emotional and intellectual skills, while striving toward independence and autonomy.

Adolescence can be a challenging time for teenagers as well as their families. In the quest for independence, many adolescents start questioning parental authority and often show signs of rebelliousness, which can create family tension.

Teenagers also typically struggle with an increasing need to belong in society. As a result, many spend more time with friends than family. This allows teens to develop and practice social skills. However, it is also within this setting that adolescents may face issues regarding peer pressure, sexual intercourse and experimentation with alcohol and drugs.

For some adolescents, these common trials can be aggravated by ongoing factors, such as a dysfunctional family, inadequate education, living in poverty and/or high-crime neighborhoods. Feelings of stress, confusion and depression from circumstances related to family, academic and social life can overwhelm many young people. This sometimes can put adolescents at risk for dropping out of school, running away from home, joining gangs, developing substance abuse or dependence, having unprotected sex, committing suicide and other types of self-destructive behaviors.

However, many studies suggest that positive family relationships are a strong protective factor against these health risks and others, including sexually transmitted diseases, teenage pregnancy and obesity.

Family support and guidance can be an effective medium for promoting values, academic success and self-confidence in adolescents. Therefore, it is crucial that parents and other caring adults stay involved in the adolescent’s life.

Other tips for helping teens cope with adolescent development include, but are not limited to:

• Discuss important topics such as puberty, sex and the dangers of alcohol and drugs with teenagers early and frequently.
  
  
• Talk with adolescents often and encourage the expression of feelings and thoughts.
  
  
• Avoid being judgmental when teens open up about their experiences and feelings.

Parents and other caregivers can also better help teenagers achieve independence by becoming informed about healthy adolescent development as well as by learning how to find supportive resources for assistance when necessary. Individuals can find information on adolescence and adolescent development in books available at libraries or bookstores and on the Internet.

Adolescence is the stage of growth and development that occurs from age 11 to 21. This period is marked by major physiologic, cognitive and behavioral changes that take place before a youngster reaches adulthood.

During this stage of development, children complete puberty (sexual maturation) and physical growth. Generally, an adolescent’s weight almost doubles and height increases by 15 to 20 percent by the time they reach adulthood. Teenagers develop important social, emotional and cognitive (intellectual) skills and also strive toward independence and autonomy. All these changes are necessary for adolescents to become mature, capable adults.

Adolescent development progresses through three stages: early (about age 11 to 13), middle (age 14 to 18) and late adolescence (age 19 to 21). Each period is usually marked by distinct characteristics of growth and development. It should be noted that the exact time frame for physical growth and sexual maturation may vary among healthy adolescents. The environment, gender and heredity can affect the rate at which adolescents develop and reach puberty.

Adolescence can be a challenging time for teenagers and their families. Adolescents must deal with rapid changes in physical appearance, hormonal fluctuations and physical abilities. Teenagers also face growing pressure to conform to social trends, peer pressure and increased expectations from family, teachers and other adults.

Adolescents often struggle with an increasing need to belong in society. As a result, many spend more time with friends than family. This allows teens to develop and practice social skills. However, it is also within this setting that adolescents can face issues regarding peer pressure, sexual intercourse and experimentation with alcohol and drugs.

Adolescents commonly start questioning parental authority and may show signs of rebelliousness. This can create a lot of tension within a teen’s family. For some adolescents, these tensions can be aggravated by environmental factors, such as a dysfunctional family, inadequate education, and living in poverty and/or high-crime neighborhoods. Such factors can put adolescents at increased risk for dropping out of school, running away from home, joining gangs, developing substance abuse or dependence, sexual promiscuity, pregnancy and other types of self-destructive behaviors.

According to the Centers for Disease Control and Prevention (CDC), the leading causes of death among adolescents in the United States – accidents, homicides and suicide – are largely preventable ones. Motor vehicle accidents account for the largest number of accidental deaths among teenagers. American Indian and Alaska Native males have the highest death rates related to motor vehicle accidents. Protective factors for avoiding accidental death resulting from automobile accidents include wearing seat belts, not driving while under the influence of alcohol or drugs and not riding in a vehicle with an intoxicated driver.

The second overall leading cause of death among adolescents, homicide, is the leading cause of death for young African Americans, the second leading cause for young Hispanics and the third leading cause for young American Indians, Alaska Natives and Asian/Pacific Islanders. The vast majority of victims of homicide are adolescent males. This may be because males are more likely to be involved in a physical fight than females.

Common feelings of stress, confusion and depression from circumstances related to family, academic and social life may overwhelm some young people and lead them to think that suicide can provide an escape or solution. The vast majority of suicides are committed by males, according to the CDC. American Indian and Alaskan Native adolescents have the highest rate of suicide.

Physical development

During early adolescence – from age 11 to 13 – young teenagers begin to experience rapid changes in body size, shape and physiology (functioning). Hormones – chemicals produced by the body – are largely responsible for these changes.

Puberty commonly begins around this time. However, it can start as early as age 8 for girls and age 9 for boys. Conversely, it may also be delayed in some cases until teens reach middle adolescence. This is part of the normal range of variation in humans and should not be a cause for concern for children or parents.

The brain releases the hormone gonadotropin-releasing hormone (GnRH) that begins the changes of puberty. GnRH signals the pituitary gland, located just beneath the brain, to release into the bloodstream two more hormones that induce pubertal growth. These are the luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Depending on the adolescent’s gender, these hormones target different parts of the body.

In boys, these hormones signal the testicles (male sexual reproductive glands) to begin producing testosterone and sperm. Testosterone is a hormone that is responsible for most of the physical changes in a boy’s body that occur during adolescence. Sperm (the male reproductive cell) is a part of seminal fluid (a whitish fluid) that forms semen, which is ejaculated during sexual arousal.

In girls, FSH and LH stimulate the ovaries (female reproductive glands), which contain eggs, to produce estrogen and progesterone – hormones that prompt the genitals and breasts to mature.

In most girls, the first sign of puberty is breast development and hair growth in the pubic area (on and around the labia), legs and armpits. Sometimes one breast will grow faster than the other, and then breast growth will even out over time. Menstruation begins about two years later on average, although these signs are reversed in some girls. Menstruation is the monthly cycle in sexually mature women that occurs when an egg released from the ovary is not fertilized, causing the mucous membrane lining of the uterus (endometrium) to shed. This results in the discharge of blood from the vagina (the passageway between the lower portion of the uterus and the outside genitals). It is common for girls to have irregular menstrual cycles for several years after starting to menstruate.

Other developmental changes include enlargement of the ovaries, uterus (a pelvic organ that nourishes the fetus during pregnancy), labia (the folds of skin that form the inner lips and outer lips of the vaginal opening) and clitoris (a small organ of erectile tissue located in front of the urethra that is involved in sexual pleasure). Also, a thickening of the endometrium and inner lining of the vagina occurs, resulting in a white, mucus-like vaginal discharge.

In most boys, the first sign of puberty is enlargement of the testicles, followed by the penis (male sex organ), and it is common for one testicle to hang lower than the other. Growth of hair in the pubic area (on and around the penis), legs, armpits, chest and face also occurs. A small amount of breast tissue may develop at this time in some boys. Growth of breast tissue in boys – a condition called gynecomastia – can appear on one or both sides of the chest, and the breast area may feel tender. In most cases, gynecomastia is a temporary condition that often goes away on its own – within a few months to a couple of years – and does not require medical treatment.

Regular use of products containing lavender and tea tree oils (e.g., soap, skin lotions, shampoo, styling products) has been linked to gynecomastia in preteen and teenage boys, according to a recent study published in the New England Journal of Medicine. These oils appear to cause an imbalance in the hormones estrogen and androgen, which control female and male sex characteristics respectively. After use of the products was discontinued by the boys in the study, the condition subsided or resolved within several months. However, more research is needed to confirm this link.

Although most boys begin to get erections during infancy, erections become common during early adolescence. An erection occurs when tissue inside the penis fills up with blood. Erections commonly cause the penis to enlarge and become very hard. Erections can occur when thinking sexual thoughts or sometimes for no reason at all. These can go away on their own or when a boy ejaculates or releases semen (a thick fluid that contains sperm and other secretions) through the urethra (opening at the tip of the penis that also expels urine).

Often during puberty, boys ejaculate at night while sleeping. These are called nocturnal emissions, or “wet dreams.” Nocturnal emissions occur as a result of a buildup of seminal fluid. Nocturnal emissions usually become less frequent as adolescent boys progress through puberty and eventually stop altogether.

For both genders, rapid musculoskeletal growth also begins in early adolescence, but peak growth is generally not reached until middle adolescence (about age 14 to 18). Boys usually peak two to three years later than girls and continue to grow for about two to three years after most girls have stopped. The adolescent growth spurt often begins with enlargement of the hands and feet followed by the arms and legs and finally by the trunk and chest. This may give young adolescents a somewhat awkward appearance temporarily.

Boys lose body fat until their growth spurt is completed and then gradually fat increases. The shoulders commonly grow wider and bodies become more muscular. Muscle mass doubles between ages 10 and 17 in boys. In contrast, girls do not lose body fat. They gradually begin to store fat from about age 6, but the location of storage changes during puberty. More fat is now stored in the stomach, breasts and upper back areas.

The throat and lungs also rapidly enlarge, causing voice changes that are usually more pronounced in boys. Skin changes also occur, such as an increase in oil production by the sebaceous (oil) glands. As a result, many teenagers develop acne. These skin lesions – also called pimples – can develop on the face, upper chest and back. Acne usually becomes less noticeable by the end of adolescence. Skin glands also begin producing chemicals that result in body odor when sweating. This is normal and can be alleviated by bathing more frequently and using plenty of deodorant.  

During adolescence the eyeballs may elongate as well. This often results in nearsightedness (myopia). Patients with myopia usually have good near vision, but poor distant vision. The condition often requires frequent changes in glasses or contact lenses during adolescence. Myopia usually stops progressing as adolescent development is completed. It should be noted that most eyes with nearsightedness are otherwise healthy.

By the time children reach early adolescence, they usually have undergone all their teeth changes – their primary canines and molars have been replaced by permanent canines, premolars and second molars. However, the jawbone (mandible) continues to grow until about age 16. Because of this, some adolescents may need braces or other orthodontic appliances to correct certain dental irregularities, such as not enough spacing between teeth or the reverse, which can occur at this time.

Cognitive development

Early adolescence marks the beginning of more complex cognitive (intellectual) thinking processes in children. Young teens usually begin to move from concrete operational thinking, which is characteristic of middle childhood, to formal operational thinking. This change involves the ability to think in a more complex manner. Teens are now beginning to think about possibilities and to form new ideas and views.

Most importantly, though, they begin to comprehend abstract terms. This means that they can understand complex and hypothetical problems involving abstract concepts, such as mathematical equations like algebra. Generally, children begin to think about the process of thinking at this stage. However, it should be noted that some adolescents acquire this capability later in development.

Although young adolescents can apply formal operational thinking skills to their schoolwork, they often are not able to do the same when it comes to personal dilemmas. This is because when emotions are involved, teenagers may be unable to treat possibilities as real entities. This can affect important decisions, such as whether or not to engage in risky behaviors such as unprotected sex or drug experimentation.

In addition, the way teenagers view moral issues tends to correspond with intellectual development. Most young adolescents tend to view right and wrong in very narrow and rigid terms. At this stage, many adolescents also begin questioning standards of morality handed down to them by authority figures, such as parents, teachers or other adults. They often embrace the behaviors and beliefs of friends. Belonging to a group of peers also allows them to avoid feeling guilty over moral infractions by shifting responsibility from the individual to the group.

Psychosocial development

As a result of the rapid physical changes beginning in early adolescence, teenagers often experience dramatic highs and lows concerning body image and self-esteem. Because puberty does not occur at the same rate for everyone, many young adolescents – who want to be accepted by their peers – tend to worry about their bodies and whether they are developing normally and are attractive.

For instance, boys may worry about whether they are big enough while girls may perceive themselves as overweight, even if they are not. Messages from the media, which typically show unrealistic body types, can influence adolescents’ self-esteem in a negative way. As a result, some boys may experiment with anabolic steroids (prescription drugs that cause tissue and muscular growth) and some girls’ obsession with body image may lead to eating disorders such as anorexia nervosa or bulimia nervosa. These negative behaviors can severely interfere with normal adolescent development, including the lack of a menstrual cycle in girls.

It is normal for young adolescents to begin establishing their individuality by increasing autonomy from family. Common behaviors at this time include avoidance of regular family activities, increased demands for privacy and argumentativeness. Young teens often select adults other than parents as role models and may also develop close relationships with teachers or their friends’ parents.

Being part of a peer group is another way of establishing personal identity for young teens. During early adolescence, peer groups are typically composed of same-sex, non-romantic friendships often in the context of cliques, gangs or clubs such as boy or girl scouts. As adolescents begin to spend more time with friends than family, clothing style and general interests are typically influenced by their peers. This sometimes can lead to familial conflicts as parents struggle with a young adolescent’s budding independence. It should be noted, though, that not all teenagers rebel and not all parents regard their child’s increasing assertiveness as a sign of disobedience. Generally, most teens still aim to please their family even while disagreeing on several issues.

At this time, most young teens are adjusting to the transition from elementary to middle school, which can be stressful. However, in most cases it is a positive type of stress associated with excitement due to academic and social growth.

Physical development

During middle adolescence, from about age 14 to 18, physical growth is usually completed for both genders. Most girls stop growing in height by age 16 and boys by age 18. In most cases, teens grow taller before their bodies fill out. Weight gain during puberty often accounts for much of an adult’s total body weight. In middle adolescence, muscular mass and strength continue to increase in boys, while lean body mass decreases in girls as body fat shifts for storage in the breast, abdomen, and upper back and hip areas.

Bone maturation, which is controlled by hormones, usually occurs after elongation (bone growth). This disparity can increase the risk of bone fractures, especially when teens engage in high-contact sports. Sports safety should be practiced to help prevent such injuries. A middle teen boy’s facial and body hair also begins to increase noticeably during this time.

During middle adolescence, the heart doubles in size and so does lung capacity. Blood pressure, volume and total blood cell count also rises, especially in boys. Teens now generally require at least nine to 10 hours of sleep a night in order to maintain optimal daytime alertness – more sleep than at any other time in life. Lack of sleep can have a negative effect on a teen’s mood, school performance and cognitive function. Studies also show that young people between 16 and 29 years of age may be more likely to be involved in automobile accidents due to falling asleep behind the wheel.

By middle adolescence, most teens have undergone puberty. Girls who have not begun menstruating usually do so by age 15 or 16. Onset of menstruation is usually determined by genetics in addition to factors including weight, chronic illnesses (e.g., diabetes) and exercise regimen. Many girls have their first gynecological exam during middle adolescence. However, health experts generally recommend that adolescent females who are sexually active, regardless of age, be examined by a gynecologist (physician who specializes in female reproductive health). Both the American Academy of Pediatrics (AAP) and American College of Obstetricians and Gynecologists (ACOG) recommend that adolescent girls see their physician for preventive healthcare visits to discuss their reproductive health, and help establish an environment where they can feel comfortable discussing health concerns. Between ages 14 to 18, boys’ sexual organs develop in size and those who have not done so already begin to experience nocturnal emissions. Voice changes may also continue in boys during middle adolescence.

Cognitive development

During middle adolescence, most teens begin high school and intellectual abilities are typically enhanced. This prompts many to question and analyze life more extensively. They often develop a personal code of ethics, which corresponds with their own beliefs and behaviors.

This new flexibility of thought has a major impact on an adolescent’s self-concept and relationships. Many begin to philosophize about the meaning of life as well as their purpose in it. Most adolescents between age 14 and 18 also start to think about the future and make plans regarding goals such as college and career paths.

Middle adolescence is a time of great variation in cognitive development among individuals. In addition, the difference between thought patterns at age 14 and age 18 is vast in both girls and boys.

Psychosocial development

During middle adolescence, a teen’s group of friends may exert less influence over them than in early adolescence. This stage is commonly characterized by plenty of experimentation. For instance, a teen may change fashion styles, groups of friends and personal interests from month to month until they discover what suits them best.

Because physical growth typically slows down at this time, teens may become more comfortable with their bodies. However, many teens also begin to experience strong emotions and rapid mood swings. Most middle adolescents continue to distance themselves emotionally from their parents in their quest for autonomy. They often channel all their emotional and sexual energy into personal relationships.

Middle adolescence usually involves a growing interest in dating. This can become an issue of conflict between teens and parents as adolescents strive for personal identity and autonomy. The past experience of the parents often influences how they cope and are able to negotiate this formative phase with their teens. Parents and other caring adults are encouraged to promote open communication while helping children make responsible decisions.

Sexual activity often varies in teenagers aged 14 to 18. The rate at which teens develop physically and sexually (puberty) in addition to societal pressures can influence sexual activity. Masturbation is very common in middle adolescence. Some middle teens engage in sexual intercourse, while others experiment with petting, kissing and mutual masturbation. Teenagers may be curious about heterosexuality, bisexuality and homosexuality. Sexual orientation is not necessarily decided during middle adolescence.  

Physical attractiveness and popularity remain important issues, both for personal self-esteem and a teen’s comfort in the ability to establish relationships. Middle teens typically spend a lot of time thinking about themselves and obsessing about physical appearance. They also tend to assume that everyone else is scrutinizing them. Self-centeredness is entirely normal at this stage of development.

A downside to this heightened self-awareness is that adolescents with physical conditions that are considered unattractive, such as acne and obesity, are at increased risk of being teased and experiencing low self-esteem. Teasing and low self-esteem can result in teenagers having difficulty in forming healthy, satisfying relationships.

Physical development  

Physical changes related to adolescent development are minimal during late adolescence, from age 19 to 21. Most healthy adolescents have completed puberty and the sexual organs are fully grown.

Older adolescent boys usually experience increased growth of facial and chest hair. Initial signs of male-pattern hair loss, such as a receding hairline, can also appear in young men who are predisposed to the hereditary condition. Both young women and men may gain weight during late adolescence, especially if activity levels are reduced.

Cognitive development

Late adolescence involves a decrease in self-centeredness. Adolescents now often begin to express interest about global concepts like justice, history, politics and patriotism. They commonly engage in moral reasoning, and many develop idealistic views. They may also become more interested in social, cultural and family traditions.

Older teens typically enjoy participating in discussions about topics of personal interest, and some may show intolerance to opposing views. Because of this developing interest and general naïvety about the world, religious or political groups and affiliations that promise easy answers to complex issues may hold great interest for some older adolescents.

The heightened ability to think abstractly also allows older teens to think more realistically about future plans and career goals. Older adolescents generally begin to think more about their emerging role in society – that of an adult.

Psychosocial development

As older teenagers become less self-centered, they begin to care more about others and relationships tend to shift from the peer group to that of the individual. Dating becomes more intimate and less superficial, and relationships increasingly involve love and commitment. Intimate relationships are an important component of identity for many older adolescents.

By the time they reach late adolescence, most teens have had sexual intercourse and many have a more stable body image since pubertal growth is now slowed or almost non-existent. Older adolescents usually become a lot more independent from their family.

Adolescence is a time of self-discovery in which young people aim to define their place in the world. During childhood, children depend entirely on parents for economic and emotional support and direction. As adolescence progresses, teenagers begin to separate emotionally from parents, and learn how to become independent and make important decisions about school, career and personal relationships.

Parents and other caregivers can better help teenagers achieve independence by becoming informed about healthy adolescent development as well as by learning how to find the resources that can help if the child veers off track. Individuals can find information on adolescence and adolescent development in schools, libraries or bookstores, by consulting a physician, and on the Internet.

Also, taking a course on parenting can be beneficial for parents of children of any age. Many colleges, universities, mental health facilities and community centers offer such courses. A mental health professional, such as a psychologist or a licensed family therapist, may be able to provide referrals for parenting courses.   

Other tips that can help parents and other caregivers promote healthy adolescent development include:

• Discuss important topics in a timely fashion. It is recommended that topics such as puberty, sex, masturbation, sexual health, contraception, assault, the dangers of gangs, alcohol, tobacco and other drugs should be discussed in a calm, open manner and preferably before a child reaches early adolescence – sometime during middle childhood. Adolescents are at increased risk for sexually transmitted diseases and pregnancy. Providing accurate information increases the likelihood that teens will act responsibly.
  
  
• Stay involved in an adolescent’s life, while respecting their need for privacy. Getting to know a teen’s friends and their parents may be helpful. Regular communication between parents can help create a safe environment for all teens in a peer group, without making them feel as if they are being closely monitored.
  
  Also, communication with teachers and other school officials on a regular basis is important. Parents can help to demonstrate the value of education and ensure children receive appropriate help (e.g., tutoring) when necessary. A positive relationship with a parent or other adult is an important protective factor for teens as they grow and explore.
  
  
• Talk with adolescents often and encourage them to express their feelings and thoughts. Avoid being judgmental when they open up about their experiences and feelings. Connected children are generally happier and do better in school and in life.
  
  
• Enforce disciplinary rules that are age appropriate. As teens mature, parents will likely need to adjust a teen’s curfew, dating privileges and other rules to encourage growing independence while continuing to maintain health and safety.
  
  
• Provide teenagers with positive feedback as well as opportunities to succeed. Treat teens with kindness and respect and avoid being overly critical. Parents who help adolescents discover and develop individual strengths are also fostering the seeds for positive self-esteem.
  
  
• Work with teens – especially those age 11 to 13 – to become more aware of the media and how to use it appropriately. For instance, discuss what TV and movies to watch and what computer games to play. Also, become aware of the music they listen to, magazines they read and Internet web sites they frequent. Some music, movies and other types of mass media can be sexually explicit and/or portray negative messages including violence against women. Whenever possible, parents should have frank discussions with their teenagers regarding such topics with an emphasis on attitudes and behaviors that can be detrimental and should not be emulated.
  
  
• Ensure that adolescents get adequate nutrition, sleep and exercise. A healthy lifestyle helps to establish good mental and physical well-being.
  
  Also, teenagers should get yearly check-ups with a primary care physician, preferably an adolescent health specialist. These medical practitioners can help teens and young adults with the complex physical, behavioral and emotional healthcare needs – from physical exams and immunizations to reproductive and mental healthcare. Preventive health visits during adolescence can offer an opportunity for physicians to educate teenagers and their parents on what comprises normal puberty including menstruation.
  
  
• Be a positive role model. The best way to raise adolescents who are loving, decent and respectful is to demonstrate the values and behavior one hopes they will develop.
  
  
• Accept personal feelings and be patient. It is normal for parents to feel bewilderment, anger and various other emotions during the teen years. Parents are encouraged to keep in mind that most children weather the growing pains of adolescence successfully and become capable adults.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Parents and/or adolescents may wish to ask their doctor or healthcare professional the following questions regarding adolescent development:

For parents:

1. My daughter has lost 15 pounds in the last three months. Does this mean she has an eating disorder?
   
   
2. I think my teen is having sex. What is the best way to discuss it with her/him?
   
   
3. I recently discovered that my daughter is using diet pills. How can I get her to stop?
   
   
4. My teen wants to get a tattoo. Are there any health risks involved?
   
   
5. How can I get my teen to confide in me more?

For teens:

1. How can I effectively treat my acne and prevent future outbreaks?
   
   
2. I am 15 and have not started menstruating. Is this normal?
   
   
3. I am 14 and male and have noticed an enlargement of breast tissue. Is this normal for guys and how can I get rid of it?
   
   
4. I recently started having sex. How can I prevent pregnancy and any sexually transmitted diseases?
   
   
5. My menstrual periods are heavy, very painful and last longer than a week. Is this normal?