Adolescence is a transitional developmental period between childhood and adulthood that is characterized by more biological, psychological, and social role changes than any other stage of life except infancy. For some adolescents, it is a period of adaptation and improved mental health, but for others it is a difficult period with increasing levels of psychological problems. The following sections highlight this critical period in a child's development when future outcomes can be dramatically altered in positive or negative directions.

Biological/Pubertal Changes
The peak of pubertal development occurs two years earlier in the average female than in the average male. Across individuals, however, there is substantial variation in the time when puberty begins, how long it continues, and when it ends. Unlike the newborn, adolescents are aware of the physical changes associated with puberty. The manner in which the family and peers respond to the adolescent's advancing development will impact how such events are experienced.

Psychological/Cognitive Changes
During adolescence, a fairly sophisticated way of thinking develops which is characterized by an ability to think in terms of possibilities, to think realistically about the future, to think about consequences, and to think about hypothetical situations. It is important to remember that there appears to be no link between physical development and cognitive development. For example, an early maturing boy who appears more developed than the majority of his peers is not necessarily able to think more abstractly or complexly than others his age.

The Family Context
Adolescence is a time of transformation in family relationships. A period of increased emotional distance in the parent-adolescent relationship tends to appear at the peak of pubertal change. Adolescents are increasingly able and willing to discuss (and argue about) issues with their parents in more complex ways, to see the flaws in their parents' arguments, to imagine what it would be like to have different parents, and to think about their parent's marital relationship separate from their own relationships with their parents. One of the major tasks for parents during this developmental period is to be responsive to adolescents' needs for increasing responsibility and decision-making power in the family while at the same time maintaining a close, positive family environment.

The Peer Context
Friendships are necessities and not luxuries and these peer relationships have positive effects on cognitive, social, language, sex role, and moral development. It is in friendship relationships that the child learns about intimacy, and these friendships serve as a basis for later close relationships. The family can provide a secure base for a child's exploration into the world of peers.

The School and Work Contexts
In addition to having an impact on cognition and achievement, school is an important environment for the development of an adolescent's personality, values, and social relationships. Physical setting, limitations in resources, philosophies of education, teacher expectations, curriculum characteristics, and interactions between teachers and students have been found to be related to a variety of child and adolescent outcomes. Children whose parents are involved in their school activities tend to do better academically.