The onset of puberty coincides with mental and emotional changes as well as physical and hormonal changes. The early teen years are an especially vulnerable time for teenagers. The Centers for Disease Control and Prevention reports that young teens are subject to moodiness and negative coping skills as they adjust to unfamiliar bodily changes and outside pressures. By the early teenage years, adolescents are capable of more complex thought patterns and have a greater ability for self-expression, which plays a role in friendship selection and maintenance.

Peer pressure works in both a positive and a negative manner in a teenager's life. Pressure from within a group encourages teens to conform. When positive values are in common, teens are less likely to engage in risky or self-destructive behaviors. The level of conformity among teenagers depends on personal characteristics, parental and community support and opportunities to participate in various groups. A teenager who experiences a warm and supportive parental relationship is less likely to give in to negative peer pressure than a teenager who is insecure and lacks confidence.

During the mid- and later teen years, adolescents make significant breaks from their parents and place a higher value on their circle of friends and peers. More comfortable with their near-adult bodies, older teenagers spend more time exploring the world through conversations and activities with their friends. Education, work and attitudes regarding establishment of families are often topics of discussion. In the later teen years, teenagers are less prone to peer pressure as their sense of personal identity solidifies. Parental encouragement and support continue to be important, especially when parents facilitate and encourage friendships with teens who also have positive parental relationships.

During the early teen years, teens socialize primarily in mixed-gender groups. In these groups, teens have opportunities to practice social skills such as communication, negotiation and problem solving. Through discussions and observations, young teens develop their own philosophy of life and begin to form their own identities. As teens progress toward adulthood, group activities are supplanted in part by dating and romantic relationships. The circle of friends remains important as a support system through the vagaries of coupling and continued self-discovery.