The Teenage Brain

From The Primal Teen by Barbara Strauch, 2003

Babies and teenagers experience the greatest change in brain structure and function. The brain’s gray outer layer thickens and then dramatically thins down. Thickening is when brain cells bloom madly called overproduction or exuberance. There is continued growth in the parietal lobes of the cortex associated with logic and spatial reasoning, and in the temporal areas linked to language. Most importantly there is continued growth in the frontal lobes or “chief executive” which peaks at puberty then steeply treks down not reaching full development and refinement until well past age twenty. This is a pruning process that brings brains back to adult levels. So as the teenage brain is reconfigured it remains more exposed and more easily wounded by excessive alcohol and drugs or a steady dose of violent video games. Jay Giedd, scientist, says “If the teenage brain is still changing so much, we have to think about what kinds of experiences we want that growing brain to have.”

As the brain develops in children and teens the inhibition machinery of the prefrontal cortex is being fine-tuned. We see the opposite in old age, inhibitions decreasing. This explains the impulsive behaviour of teens as they deal with an increasingly complex world, e.g. school work getting harder and more complex social relationships, on their own. This is why it is essential that parents maintain their role as parents and not their teen’s friend. Parents need to act as though they are their teenagers “frontal cortex” by talking through possibilities and options.

The brain responds to experiences by connecting up synapses so that it can work better and more efficiently – it becomes developed and enriched. The key ingredients are good diet, exercise for good blood flow, challenges or new experiences and love. This is true at all ages.

Myelination is the wrapping of white matter (fat) around the axon arms that extend from neuron cell bodies to insulate and increase the speed of the brains electrical signals. This process is happening in the teenage brain, which explains why their thinking is sometimes not up to speed. This process jumps 100% during teenage years. The cingulate, the area of the brain that involves emotion, is undergoing this process, which may explain why teens can be so reactive. The connections between emotional experience and cognitive processes are still being integrated.

When teens were tested to find out where the brain lights up in response to a picture of a fearful face it was the amygdala, which is responsible for reactions such as fight, flight or anger. In adults however it was the frontal cortex where the process is more about “should I be afraid?”, “have I seen this before”. This is no doubt because the frontal cortex is not fully wired up yet in teens. As it develops teens become calmer, more directed and focused.

A longitudinal study of adolescent health seems to point to factors such as having one adult who cares and being connected to school as being the determinants of success.

Risk seems to be part of the developmental task of adolescents with most coming out fine. Many child psychologists say teenagers do risky things to find out who they are and where they fit in. Great if teens can take risks in performance, advanced classes, sport, adventure and where there is some adult involvement and guidance. One psychologist found that teens don’t necessarily think they’re immortal and are scared of things like dying, parents dying, getting hurt, bad grades and getting kicked out of their group. Teens do think using what skills and knowledge they have.

Dopamine is heavily involved in what’s known as the pleasure-and-reward circuit in the brain. This is the part that makes us feel good and pushes us to reach for the same thing again. We seek rewards that relate to issues of survival like sex and eating. It’s possible to get too much dopamine as in drug addiction when the brain’s dopamine neurons are overstimulated. Then the brain tries to cut back on dopamine receptors. This can also happen when teens are highly stressed prompting teens to take more drugs or push harder on the accelerator. We are also wired to seek out and enjoy new things. That’s how we find new partners and food but also danger. It gets us off the couch. During adolescence dopamine is declining except in the prefrontal cortex where it is still increasing. This enables the brain to establish the connections it needs for a lifetime. However this general drop in dopamine levels may be the factor that drives teens to seek more stimulating activities than adults in an effort to get as the same bang for their buck. Psychiatrists say young people need to see a range of ways of being a teenager not just being successful academically and they need to be able to cope with making some mistakes.

In research at Pennsylvania State University a study found that impact from the environment trumped the effects of testosterone. So when parent-teenager relations are poor high-testosterone sons are more likely to engage in risky behaviour such as truancy, sex, lying, drinking and stealing. Low-testosterone sons with poor parental relationships are more likely to be depressed. It may be due to a link between testosterone and serotonin, which is a neurotransmitter that has a calming effect. Low-estosterone daughters who had poor relations with their mothers are more likely to do risky things, while those who had poor relations with their fathers are more likely to report signs of depression. The good news is that for those boys and girls who have good relationships with their families high or low levels of testosterone don’t seem to matter at all.

Sleep researchers say there is a shift in sleep timing that seems to emerge at puberty. By measuring levels of melatonin in saliva they found that as adolescence progresses teenagers secrete melatonin later and later in the night. Teenagers tend to push this further and can get stuck in unhealthy sleep patterns. They actually need 9 hours to get the sleep required to “retune”. Neurological systems may need time to disengage so they can connect better later, in a similar way to parts of an orchestra tuning up alone before they can successfully play together. Without this emotions can spin out of control. Teenagers are the most sleep-deprived segment of the population. They may need our help to organize their time in order to get sufficient sleep.

Studies show that teens who drink excessive alcohol eg 2 drinks a day for 2 years, experience a 10% memory loss and less activity in areas of the brain used for certain cognitive tasks such as finding their way somewhere or remembering what to get from a store. These are permanent effects. Alcohol has less of a sedating effect on young people than adults wrongly giving the impression that they their functioning is ok. Both alcohol and nicotine reduce the size of the hippocampus, the area of the brain involved in learning and memory. Nicotine has been found to lower serotonin levels, which is a marker for heightened risk of depression.

So because teenagers’ brains are still developing it still matters what parents, friends and teachers do. We can still have an impact. We can cut them some slack knowing they’re in a process. We can continue to offer challenges, opportunities and adventures. We need to continue to support and believe in them.

Implications for parenting:

  • Allow processing time when communicating with teens. Go back later to check for understanding.
  • Allow for teens to misinterpret or not accurately pick up emotions in others – be prepared to explain, clarify and coach.
  • Don’t take reactions personally.
  • Give one instruction at a time eg “vacuum your room” not “vacuum your room, change your sheets and do your washing”.
  • Don’t assume your teen is not thinking but they may not yet have the skills to consider other options.
  • Give teens opportunities to take positive risks so they are not limited to drugs, alcohol and sex.
  • Encourage the ideas that mistakes and trial and error are part of life not failure and that there a range of ways of being successful for instance the kind of person you are and healthy relationships.
  • Maintaining good relationships between parents and their teens has a positive impact on teens mental health.

See my recommended reading list:

  • Raising Teens Today, Lambie and Simmonds
  • The Politically Incorrect Guide to Teenagers, Nigel Latta
  • Kids are Worth It, Barbara Coloroso  The Whole Brain Child, Daniel Siegel
  • Boundaries with Teens, John Townsend (Christian content)
  • Real Wired Child, Michael Carr-Gregg