Adolescence is considered as a normal part of the human life span, connecting middle childhood and young adulthood, this period consists of three separate phases: early, middle, and late adolescence.
The adolescent years extend roughly from age 10 to age 22. It is common to mark the beginning of the teenage years as the entrance to adolescence; most people consider that the onset of puberty, or the beginning of sexual maturity, as a sign of an individual's passage from middle childhood to adolescence.
While the physical changes of puberty are an important indicator signalling adolescent development, many other kinds of changes also occur during the adolescent years; cognitive, self-concept, social / moral reasoning and the ability to think abstractly.
Although this developmental period of life needn't be an uncommonly stressful time, adolescents do encounter stresses. Most adolescents are well adjusted individuals not depressed mixed up people as is commonly thought, possessing rather than lacking in self-control and confidence. At the same time it must be recognised some adolescents exhibit signs of disturbance and can suffer severe life crisis.
Early adolescence
The initial period of change that marks the adolescent years is called early adolescence, which extends roughly from age 10 to age 14. During these years, the individual is expected to make certain transitions. An early adolescent is expected to move from the security of a junior school to the stress of a secondary school education. However, in preindustrial societies, where the notion of teachers and schools differs from that in industrial societies, education occurs by working closely with skilled adults, often as an apprentice. Formal education may be available but limited to a small portion of male youths for a few hours weekly. Unlike youths from industrialised countries, who spend a great portion of their time with peers, adolescents in preindustrial