Parenting the teenage brain: a user’s guide

In Part I of this two-part mini series we look at changes in the teenage brain and how these can affect behaviour

The challenges of the teenage years are as normal a stage of child development as the sleepless nights, endless bodily fluids, food-spattered walls and temper tantrums of the first two years. Photograph: iStock

The teenage brain – a work in progress

Adolescence has had a very bad press. Horror stories of unpredictable mood swings, secrecy, dodgy friends, general rebellion in the ranks, and experimenting with the dangers of sex, drugs, and what passes these days for rock and roll, all seem to paint a picture of things going badly wrong. And yet the challenges of the teenage years are as normal a stage of child development as the sleepless nights, endless bodily fluids, food-spattered walls and temper tantrums of the first two years.

In fact, these two phases of development share something very similar – the human brain is going through some of the most radical changes it will ever experience in such a brief period of time.

So, what’s going on in there and how can parents support their teenager as their brain appears to be wreaking havoc all around them?

Childhood and the brain-building project

At birth, the human brain arrives a bit like a kit where about half of the pieces have already been put together, but the rest still need to be assembled. The process of building the brain out of these remaining pieces is one of trial and error as brain cells try and work out which connections are the strongest and most effective, and which ones aren’t. These connections happen at the rate of about two million per second in the first two years of life, and by the end of this phase the brain has a hundred trillion connections across all of its cells – roughly twice the number needed in adult life.


Despite all this potential, the unsuspecting two-year-old doesn’t have enough life experiences for the brain to know what to do with all of these connections – and that’s what childhood is pretty much all about. Taking all of this potential, shaping it and pruning it until we have the fully formed adult brain at the age of 25. Yes, you read that correctly – it takes 25 years for the human brain to mature from the half-completed kit at birth to the fully functioning article needed to grapple with the complexities of adult life.

Adolescence and the preparation for independence

By the time the brain arrives at puberty, there’s been a steady period of roughly 10 years gradually cutting back connections and shaping the brain in preparation for the next explosive phase of development. Having ideally settled into the safe rhythms of family and home life, friendships and school, the brain now needs to prepare the maturing child to leave all of this behind and launch themselves out into a world which looks in equal measure exciting and full of possibilities, and terrifying and full of danger.

To help this to happen, the brain develops according to a pre-set pattern that, in the short term, produces behaviours from the young person that can be challenging, confusing and sometimes downright frightening for parents. These emotions can be helpful in offering an insight into how teenagers might be feeling as their bodies, brains and personalities suddenly change almost beyond recognition.

The areas of the brain that are responsible for self-identity, problem-solving, managing emotions and impulses, understanding others, appreciating consequences and managing risk are at this point undeveloped. Up to now, children have relied on adults around them to help them to negotiate these. From here, they’ll need to begin to learn how to manage independently in preparation for adult life. To kick-start this learning, the brain suddenly goes through a dramatic process of growing millions of new cells, connecting them up in the same trial and error fashion as early childhood, and then pruning them back into the shape that’s needed.

For the newly-arriving teenager, the last time this happened was in the first two years of their life, and they probably don’t remember any of it. All they know is that a nicely ordered world appears to be have been turned inside out, and they can’t understand why. Is it any wonder, then, that there suddenly appears to be an alien living in the house?

Parenting and the social brain

There are two final pieces of the biological puzzle that can help parents to work out the best way to support their teenager through this vital stage of their development. The first is that, although the basic structures of the brain are complete by the age of 25, it continues to fine-tune and adapt until we die. As we go through life’s challenges and experiences, the brain is constantly checking in with itself and making changes as we learn from these. Fundamentally, this means you absolutely can teach an old dog new tricks, and these new tricks are usually learned when things get difficult. As a parent, you really need to know this since it will provide you with one of the essential keys to dealing with things successfully.

The second piece of the puzzle is that recent research has begun to identify that the brain is a social organ. Unlike all of the other essential organs of the body, it needs input from the outside world in general, and other people in particular, so it can develop the connections and structures to do its job and help us to function socially. Our brains grow, develop and learn in a rich mixture of social relationships over a lifetime of experiences. In other words, brains need other brains.

What this all seems to boil down to is that parenting is a complex process of two-way learning. Just as teenagers are busy building the basic structures for their adult brains, parents are also fine-tuning and tweaking with their already-developed structures as they increase their knowledge and experience of relating with their child.

Although the starting points are different, children and parents are learning from one other on the hoof, trying things out via that time-honoured method of experimental trial and error.

Part 2: How to manage conflict

– Fred Ehresmann is senior UK trainer for Parents Plus Charity and senior lecturer in mental health at the University of the West of England. For more information see