Image of brain lobes
Brain lobes by Allan Ajifo CC BY 2.0

Adolescent development

As an individual transforms from a child to an adult in the period known as adolescence, they experience great physical, neurological and psychological changes. The various areas of development (physical, neurological, emotional and social) interact closely with one another, and a physical change may trigger a positive or negative emotional response in the adolescent.

Physical development

Puberty is a gradual process and begins with an increase in hormone production that brings about a range of physical changes. These include rapid growth in an individual’s height and weight and the emergence of secondary sexual characteristics as a child moves towards an adult state.

For girls these include:

  • the onset of ovulation and menstruation
  • development of breasts
  • growth of body, underarm and pubic hair.

For boys:

  • a deeper voice
  • erections and wet dreams
  • growth of body, facial, underarm and pubic hair.

The speed of these visible changes, coupled with a difference in hormone levels, can lead some adolescents to worry about their appearance. There is a wide range of what can be considered ‘normal’ development, as changes can occur at different rates depending on the individual. Less visible are the internal physiological, cognitive, and emotional changes that occur during puberty.

Neurological development

A human brain is not fully developed when a person reaches puberty, but although the brain doesn’t grow much in absolute size during adolescence, it does change rapidly. Neurons that are not being used are ‘pruned’, while others that are actively used grow a fatty sheath (are ‘myelinated’) so that they can conduct very rapidly.

The limbic system and amygdala, which are situated deep inside the brain, are very important for emotions and ‘rewards’. These develop relatively early, whereas the frontal lobe of the brain, which is situated just behind the forehead, is particularly important for executive functioning, which includes planning ahead, reasoning, considered decision-making and self-discipline. It is one of the last areas to mature, and is not fully mature until at least 25 years of age. This may explain why adolescents and young people tend to take risks and are prone to ‘hot cognitions’, making decisions rooted in emotions and experiences rather than logical reasoning.

Normal, healthy development is uneven

Changes on these multiple fronts do not always happen in sync. For example, an adolescent girl may look physically mature, but psychologically she is still developing. Her appearance can lead people to believe and expect that she has mature thinking patterns or can manage her emotions, and this may not be the case. Conversely, another girl who looks physically immature may have more mature ways of thinking.

Adolescent development: psychological and social

During this time of hormonal and neurodevelopmental transitions, adolescents’ brains undergo cognitive changes where abstract and creative thinking patterns begin to develop. At this time, adolescents develop stronger reasoning skills as well as logical and moral thinking. They are also transition from dependent to interdependent relationships and establishing their personal and social identity, including through exploring their sexuality. Behaviours that are characteristic to adolescence are self-consciousness, rapid and mixed mood changes, risk taking, novelty seeking and building social capital. Adolescents are particularly influenced by social signals, including peer pressure, desire to be accepted and cultural learning.

Implications for health and behaviour

Adolescent development and behaviours can have a big impact on their current as well as future state of health. For example, diet, exercise and substance use can have health compromising consequences in adulthood leading to serious public health implications. At the same time, research shows that adolescence is a time when the brain exhibits high neural plasticity, which facilitates maximal learning. It is therefore vital to harness this crucial opportunity to provide education and support for adolescents to form positive health behaviours.

Let’s discuss

Considering emotional and social development, as well as how attitudes and habits form in this period can affect an individual throughout their lifetime, try to think about your own adolescent behaviours. Can you think of an instance where something you did as an adolescent still affects you today? Do you think this was directly related to the developmental changes you were experiencing? Only share if you feel comfortable doing so.

Share this article:

This article is from the free online course:

Improving the Health of Women, Children and Adolescents: from Evidence to Action

London School of Hygiene & Tropical Medicine