Teenage kicks in the hormones
What makes the teenage years so awkward for everyone? A lot has to do with maturing and the wiring processes in the teenage brain, writes CLAIRE O’CONNELL
SLEEPING UNTIL lunchtime at weekends. Spot creams in the bathroom cabinet. The occasional slammed door and maybe even risky behaviours, such as e experimenting with drugs or driving too fast.
Teenagers are all individuals but if there’s one in your household – or maybe you are one yourself – at least some of the above is probably familiar.
Still, between the refrains of “turn down the volume” and “what did you do to your hair?”, spare a thought for the underlying biology of that transition between childhood and adulthood.
Hormones are one of the most famous game-changers, and they start to make their presence felt during puberty, says Dr Sinead Murphy, a lecturer in paediatrics at University College Dublin and a consultant paediatrician at Temple St Hospital.
“Puberty is basically controlled by the hypothalamus, which releases a hormone that acts on the ovaries in females and the testes in males. That causes them to produce the sex hormones, which can affect behaviour,” she says.
However, it’s not all even-keeled: the hormones tend to get released in pulses during adolescence, and girls could experience the cyclical nature of hormones even before menstruation starts, she adds.
Meanwhile, growth hormone, which pretty much does what it says on the tin, gets secreted mainly during sleep, which might be a reason to be lenient about the long lie-ins.
Puberty hormones may also affect brain development, but we still have plenty to learn about that. Dr Anne-Lise Goddings at University College London is studying the links.
“We now know that how the brain functions when asked to do tasks on a computer and in a brain scanner changes not just with age in adolescence, but also with their levels of androgens and oestrogens,” she says. “And how the structure changes across adolescence is related to puberty and the hormones that cause it too.”
For now though, the mechanisms are unclear. “So far, we can’t be sure exactly how the hormones cause these changes,” says Goddings, who is a Medical Research Council clinical training research fellow and paediatric specialty registrar at UCL’s Institute of Child Health and Institute of Cognitive Neuroscience. “They may act directly on the brain using hormone receptors, or might work by changing our behaviour, which in turn changes the structure and function of the brain.”
More generally, magnetic resonance imaging (MRI) has been highlighting that in the adolescent and teenage years the brain is quite distinct from childhood and adulthood.