Adolescence, the period between childhood and adulthood, is rightly viewed as a period of enormous change.

Recent research, however, has established that hormones are not the only culprit. There are also many other elements of the body’s biochemistry and physiology that combine to make adolescence something of a ‘perfect storm’.

This page explains more about the changes to adolescents’ brains and bodies, to help parents to understand more about why their children may behave in certain ways.

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Adolescence: Brain vs. Hormones

There are two main elements that affect maturity of both body and emotions.

1. Hormonal changes lead to and guide the body through puberty, resulting in sexual maturity.

   These include the sex hormones, oestrogen in girls and testosterone in boys. They were once thought to be the main cause of most of the behavioural changes in puberty, particularly increased aggression and mood swings. There are, certainly, massive changes in hormonal levels during puberty in at least three different hormonal systems.

   However, there is no link between blood testosterone levels and levels of aggression in young men.

   So what is causing these behavioural changes?

2. The brain develops and changes throughout childhood and adolescence.

   It used to be thought that the brain was basically mature from a very early stage, but recent research has found that, in fact, parts of the brain continue to mature well past the age of 18.

   It is generally agreed that the brain kick-starts the hormonal surges that lead to puberty. It is not, therefore, the hormones that lead to changes in the brain, but changes in the brain that lead to hormonal surges and, ultimately, to puberty.

   In young people who do not undergo puberty because of hormonal problems, the brain continues to mature perfectly normally, and their reasoning, ability to assess risks, and other thinking abilities, develop in line with their peers.

It seems, therefore, that although the brain and hormonal systems come together to create the various changes seen during adolescence, the majority of the behavioural changes are due to the brain.

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Brain Changes During Adolescence

There are two main features of the brain that change massively during the maturation process. Both, unfortunately, seem to coincide with adolescence:

1. Myelin is added to neurones, which has the effect of speeding up neural messages: everything gets through quicker.
2. The brain seems to take ‘time out’ to rewire the pre-frontal cortex, the area primarily responsible for things like planning, organisation and risk assessment. The huge number of neural connections is ‘pruned’, probably to make it more efficient, but while this process is happening the brain actually functions rather less effectively.

Together, these two result in some key behavioural changes that are seen during adolescence:

• An increase in excitement-seeking.

  This is basically down to an increased need for sensory input, because messages are travelling quicker. It may manifest itself as adrenaline-seeking, for example, through theme park visits or high risk sports. You may also see teenagers respond to louder music, or brighter lights: there is a reason why nightclubs target teens, and why clubbing becomes less attractive as you get older.

• A decreased ability to plan, organise and assess risk accurately

  The changes in the pre-frontal cortex result in a general inability to make good decisions, and particularly to assess risk. Unfortunately, since this coincides with the increased need for sensory input, it is also why teenage boys have a relatively higher mortality rate than they should.

• A tendency to have more heightened emotional responses

  Like the need to seek more sensory input, teenagers tend to feel things more extremely. They are more likely to become angry, sad, excited and happy: everything is more profound. This results in ‘mood swings’.

• A focus on self, to the exclusion of others

  Teenagers are not ‘being selfish’. They genuinely do struggle to recognise emotions in others, probably because of the rewiring of the pre-frontal cortex, which makes them extremely self-centred. They are unlikely to be able to assess the impact of their actions on others.

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Adolescence and Sleep

One key issue which will be familiar to any parent of an adolescence is sleep, and particularly the need to sleep from 2am until noon. There seem to be several issues here.

The first is that teenagers have a physiological need for more sleep, probably because they are growing rapidly.

This generally manifests as increased sleepiness, and longer sleeping if the opportunity is offered.

At the same time, there is a change to the secretion of the hormone melatonin, which controls sleep.

This is released later in the evening during puberty, which means that teenagers are more likely to want to go to sleep slightly later. It does not mean that they have to do so, but they will tend to stay up later if possible.

This, of course, probably was not a problem a few hundred years ago. Adolescents would have been working, and would therefore have been physically tired. There was little to keep them awake after dark, so they would simply have slept.

Now, of course, there are multiple distractions. There is evidence that the light from computer and TV screens interferes with melatonin secretion anyway (there is more about this in our page on The Importance of Sleep), and the result is that teenagers are distracting themselves into staying up even later.

The third issue that coincides is one of habit, and is similar to jet lag.

Anyone who has travelled long distance will recognise that it is much easier to adapt to jet lag when travelling westwards: that is, if it involves a longer day, and later sleep times. Moving in the other direction is much harder.

The same thing applies to young people. Once they have slid gently into a later sleeping pattern, perhaps during a long summer holiday, with late nights and late mornings, it is much harder to get up earlier for school.

Our weekly pattern of work also means that just as their bodies start to re-adapt to ‘normal’ time again, the weekend intervenes, and they slip back into the later time zone.

  

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Adolescence is a phase…

Adolescence is a difficult period for those experiencing it.

It can also be extremely difficult for those around them, particularly their parents.

It is important to remember that you, and your adolescent child, will get through it. Like everything else, this is a phase, a vital phase of development and it will pass. Stay calm and the storm will eventually be over.