If you’re the parent of teenage offspring, particularly if your progeny is currently lounging around the house having broken up from school, college or university and you’re grieving the loss of old fashioned apprenticeships, then you’ll be accustomed to glares, back-chat, mood-swings, bouts of selfishness and sulks followed by demands for money.

You may be thinking, ‘What happened to my polite, good humoured little darling who was happy to help wash the car for pocket money?’ Take heart, you’re not alone as many parents of teenagers will tell you and it will pass. But why does this happen to our charming sons and daughters who seem to loose the ability for empathy overnight in exchange for acne and a permanent scowl?

Well, the teenage brain is very much a work in progress. Massive structural changes happen to the brain prior to and during puberty and this neural upheaval may be at the heart of your teenager’s personality change.

First up, the teenage brain reacts very differently to stress and anxiety than adult brains do, according to the research of physiologist Sheryl Smith. Whilst adult brains release chemicals to calm down stress reactions, teenage brains amplify the chemical reaction to stress and the resulting emotional behaviour, such as anger or tears, will be more pronounced. So whilst to you it may seem that your teenager is over reacting, this may be the only response available to him or her.

Whilst in the womb and for a short time after birth, a baby’s brain will grow rapidly and make an astonishing number of neural connections (to enable electro chemical messages to fire across different regions of the brain and down through the spinal cord). At this stage the brain has many more connections than it requires and as the baby develops and learns, some of these connections are pruned down. Now MRI scans of children taken over a series of years have shown that humans experience a second spurt of brain growth just prior to puberty.

This shake-up of the neural network coincides with the mood-swings and personality changes that we experience in our teenage sons and daughters. Can you blame them? They have to rewire their brains at the same time as coping with a growing interest in sexual matters and sitting important exams!

Because this brain development and rewiring happens unevenly across the brain, different areas responsible for things such as emotions, language skills, reasoning etcetera mature at different times. A teenager is not a small adult: they are a very different creature altogether. For example, don’t assume that because you’ve laid out an argument that your teenager is interpreting it in the same way that you’ve presented it. The seat of reasoning – the frontal cortex – is continuing to develop, and if he or she doesn’t have the neural structure in place, you cannot expect your adolescent to really think things through at the same level as an adult.

What about the teenage obsession with what others think about them? Isabelle Rosso, who has worked on the MRI studies, also found that as adolescents’ abstract reasoning skills increased, so did their levels of social anxiety. Part of abstract reasoning includes being able judge what others are thinking and feeling but this may contribute to increased feelings of worry about how others view oneself.

Teenagers are frequently chastised for needless risk taking and believing they are invincible (the high rate of accidents involving teenage drivers sadly supports this). According to Professor Laurence Steinberg, heightened risk taking in adolescence is the result of competition between two very different brain systems: the ‘socio-emotional’ and ‘cognitive-control’ networks.

During adolescence, the socio-emotional system becomes more assertive, allowing your teenager to become more easily aroused and experience more intense emotion. They also become more sensitive to social influence. Later on the cognitive-control system, that regulates behaviour and makes decisions, gradually gains influence – but this part doesn’t fully mature until your child’s mid-twenties and perhaps beyond.

Any parent who has tried to rouse their teenager before noon on a Sunday will tell you that teenage sleep patterns also differ from adults. Studies show that adolescents need as much sleep as younger children (about 8 hours), that daytime sleepiness increases and the patterns of sleep shift towards later waking and sleeping times. Because of school times, teenagers try to catch up on sleep by having lie ins at weekends but these irregular sleep patterns can decrease the quality of sleep leading to irritability.

As much as teenagers are a mystery to us, let’s not forget that as adults we are equally as perplexing to them. I’ll leave you with an observation from Mark Twain:

“When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty- one, I was astonished by how much he’d learned in seven years.”