How can you tell when behaviors and feelings are part of typical teenage angst or something more concerning? This blog will look at what is happening in the teenage brain and my follow-up blog will discuss strategies for parents and teens to more positively address this critical and confusing period of development.

First, lets talk about the teenage brain- it’s not just a smaller or less developed version of our adult brain. There are parts that can function in opposite or different ways than its future matured self. Those differences can impact teens’ reactions to stress as well as the development of mental illnesses.

Adolescence is a very unique and critical point in our development. Our developing adolescent brain is actually more capable but also more vulnerable than any other point of our development. Teen brains are uniquely primed to learn and absorb knowledge and experiences, which the brain uses to shape and prioritize development. The teenage brain has a large quantity of grey matter (large quantities of neurons that allow us to process and release information) but a smaller amount of white matter (tissue, axons, and myelin which allows the areas of the brain to interconnect and send messages). This means that teens have an advantage in absorbing information, but have a slower ability or difficulty communicating it throughout their brain or to the world around them. Also, a teen’s prefrontal cortex is developing throughout their adolescence until around the age of 25. This is the area of our brain that is responsible for more complex problem-solving and decision making. It aides us in pausing our reactions and thinking through our responses. So not only is this area of the brain still developing, the parts of it that do develop during adolescence will communicate with each other at a slower rate because their myelin is still developing.

To visualize this, imagine that you can only communicate through paper mail again at a time when those around you are able to text to each other. The differences in time that it takes your message to be read can lead to miscommunication or misunderstandings, especially if your impulsive or more primitive feelings and fears were still able to communicate with your brain at the speed of texting. This occurs because a teen’s amygdala is still in the drivers seat instead of their prefrontal cortex since their prefrontal cortex is still developing.

This is how you may find yourselves repeatedly in “you knew better” situations, because even though they knew better, their brain did not communicate with itself in time and instead instinct was primed towards choosing rewards instead of noticing consequences. We’ll look more at that later.

Grey Matter and White Matter- MYELIN

Our thoughts, behaviors, and feelings are the result of neurons communicating with each other through electrical signals. These signals travel through axons that are coated in myelin, a fatty substance that helps contain those electrical signals, much like the coating in the wiring in your homes to insulate the electric currents and keep electricity flowing in its given direction without escaping before reaching its destination. The myelin in our brain allows these messages between neurons to travel faster and it allows us to send new messages without needing recovery times. It is how the areas in our brain are functionally connected and can quickly communicate. Skills like inhibition, impulse control, coping, and calming strategies aren’t as quickly communicated/recalled when our brain is less myelinated. Important responses may also be lost in the moment, in favor of more impulsive or reactive responses. Remember, this is all happening at a time when the teenage brain is also being flooded with new information, experiences, and development.

Myelin is thinner in adolescence and continues to develop into our 30’s. This means that teens have less myelin at a time when they are obtaining more information with those larger amounts of grey matter. This has a big impact on the connections in the brain and teen’s ability for learning and problem solving, especially when stressed. These connections within the brain begin to develop from back to front meaning the last parts to develop and connect are the frontal lobes and prefrontal cortex, which don’t fully develop until adulthood but are key areas for executive functioning.

As teens mature, they will begin to lose grey matter and increase white matter. Think of this as “use it or lose it”. This is a wonderful time when teens can learn a huge variety of skills and information and learn behaviors based on their experiences. This occurs in the brain so we can survive in the environments we grow up in, learning critical responses to those environments based on our interactions with them and prioritizing specific areas to develop in response. That is why grey matter and neural plasticity is higher in childhood and adolescence because we need to be able to adapt to our environment. The negative side of this is that negative environments or negative responses can also become prioritized and shape unhealthy behaviors or development, increasing risks for anxiety, depression, or emotional trauma. The teen brain is so primed to learned, but with the lack of higher order executive functioning development, they are also vulnerable to learning the wrong things. Teens are driven by dopamine (pleasure or gratification-seeking) as well as by their experiences, meaning if they don’t experience consequences with risk-taking behaviors then they’re more likely to repeat them than adults.

Using positive interventions at this time, like family involvement, therapy, tutoring, etc., can have a profound impact due to a teen’s increased neural plasticity.

Note, Trauma and disorders like ADHD can impact these general guidelines for brain development and myelination, including the timing of development and which brain structures are prioritized. You can learn more about those impacts here:

Hormones & Dopamine

Teen brains are interacting with the effects of hormones at a level that they never experienced before outside of utero and it takes their brains time to learn to regulate them. The type, timing, and level of hormones plays out differently between genders as well as their stages of development. Boys will have around 30 times the amount of testosterone in their body from prepubescence to early adulthood. Girls progesterone and estrogen spike in concentration, building in the year prior to menstruation, often leaving parents feeling that the year before their teens’ periods were particularly difficult.

Teens don’t actually have more hormones overall than adults, their brains’ just haven’t learned how to manage them or their changing concentrations yet.

Remember that the structures of the brain best used for emotional regulation and myelin connections are still developing, leaving teens at a disadvantage. At times it can be like having a novice driver in a racecar (their brains souped up with excess grey matter) on a slick track (their lack of executive functioning, regulation, or myelination). Accidents and mistakes will occur. Parents and teens- remind yourself that it is normal and even expected that mistakes will occur. Use them as opportunities for learning and reducing further risks instead of moments of criticism and guilt. My next blog will have more details for specific strategies for teens and parents to actively address these concerns and how to decrease those risks.

Despite popular belief, teens aren’t actually more irrational. Instead, dopamine is increased when released in the teen brain, meaning they are more primed for sensation-seeking. Because those frontal lobes and myelin levels aren’t fully developed, they have to take more time and use more structures in their brain to control their impulses and resist responses that have negative consequences, especially if they feel the immediate rewards could potentially outweigh the possible risk. It also takes teen brains longer to realize when ‘not to do something’ than when ‘to do something’. It’s easier for a teen to ‘reason away’ the risk because of the benefit of the dopamine release in anticipation. Teens’ dopamine levels are further flooded by daily interactions with social media and technology, making the regulation of dopamine in the brain even more difficult in modern day teens.

Gender Differences

As a parent, or if you work with teens closely, you may have noticed some general differences in how teens communicate (or don’t communicate) their feelings or worries as well as how they approach school work or organization. Some of this can be the result of developmental differences during adolescence. These are not guarantees, but can be common occurrences. Teen girls can have a larger corpus callosum and the areas of the brain that communicate with itself or ‘wires the brain together’ can develop earlier in girls-their frontal lobe and parietotemporal area. This can lead to girls having increased language development and communication abilities, multitasking, and decision-making in their adolescence compared to adolescent boys. This difference can last up to a year and a half! Boys may take longer to develop their organization and attention skills, usually with the greatest difference of this skill being present in adolescence as opposed to adulthood.

So if you feel like you are struggling to pull a conversation out of your teen son, there can be a structural reason for this. Instead of sitting in future frustration or personalizing it, you can help them build those skills until their brains are able to fully take it on themselves. If your teen daughter has a tendency to make negative comments, perhaps without thinking them through, remember the race car analogy. Her language and communication skills can be rapidly growing, while her impulse control and inhibition is still developing. Again, try to build her emotional awareness (empathy) and establish healthy boundaries before personalizing the situation.

This final slide is a reminder of some of the differences between the teen and adult brains. It is only natural in the everyday bustle of our lives to forgot how different our teen’s processing and experiences can be from ours, but it is important to remember what can be happening under the surface without our awareness.

My next blog will be about strategies for parents and teens to not only mitigate some of these impacts but also to help identify when behaviors or emotions are more concerning and could be signs of clinical needs or mental illness.

You can find more information about teens and mental health here: