Adolescence is a period of biological development, psychological, sexual and social immediately following the children and that begins with puberty. It is a life span between puberty and adulthood, their range of duration varies according to different sources and medical opinions, scientific and psychological, is generally framed their beginning between 10 and 12 years, and its completion at 19 or 24.
Previously, the World Health Organization regarded adolescence as the period between 10 and 19 years, within the period of the youth between 10 and 24 years, puberty or adolescence initial is the first stage, normally begins at the age of 10 in girls and 11 in boys and goes up to 14-15 years. Adolescence middle and late stretches, up to 19 years of age. The teens then followed the youth to the full, from age 20 to 24 years.
Some psychologists believe that adolescence covers up to 21 years of age, and some authors have even extended in recent studies the teen years to 25 years.
The World Health Organization (WHO) estimates that one out of every five people in the world is an adolescent, and 85 percent of them live in poor countries or middle-income, and about 1.7 million of them die each year.5 The WHO defines adolescence as the stage between 10 or 11 years to 19 years of age, and considered two phases: early adolescence, 10, or 11 to 14 or 15 years, and late adolescence, 15 to 19 years of age. however, the condition of youth is not uniform and varies according to the social group that is deemed suitable.
Adolescence is characterized by physical growth and psychological development, and is the phase of human development situated between childhood and adulthood. This transition should be considered a biological phenomenon, cultural and social.
Many cultures differ in respect to what is the age at which people become adults. In several regions, the step of the adolescence to the adulthood is linked to ceremonies and/or festivals, as for example in the Bnei Mitzvah, which is celebrated at the age of 12 for girls and 13 years for children. Although there is no consensus on the age at the end of adolescence, psychologists such as Erik Erikson believe that adolescence ranges from twelve or thirteen to twenty or twenty-one years. According to Erik Erikson, this period from 13 to 21 years is the search for identity, defines the individual for his entire adult life being fully consolidated the personality from the age of 21, however, not be generalized, since the end of adolescence depends on the psychological development of children, the exact age at which it ends is not uniform and will depend on each individual, etc.
Growth and development
From the practical point of view, the changes are usual in the growth they have three great features:
Are performed in a sequential manner, that is to say, a few characteristics appear before they appear other, as is the case of the growth of the breasts before the onset of menstruation (or rule, or period), and the pubic hair before the armpits, the lower limbs grow first, that the trunk, the testicles increase before the penis, etc.
The onset time, magnitude and rate of each event is considerably variable between the ages and the sexes.
Each event's growth follows the law of the individual variability of development. Each individual has an own way of being and preserved through the years of adolescence and is influenced by various factors, such as ethnicity, genetic makeup or family, nutrition, and functioning endocrine and socio-cultural context. Based on this, the assessment of sexual maturation is often more valuable from the clinical point of view than the chronological age, that is the correlation that usually worries parents and the teenager.