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Why teens act the way they do — it’s brain science

Understanding your teen’s brain development can help you support their health

Parenting a teen can be, well, let’s call it exciting! Teen drama, intense crushes, or shifting moods are some of the behaviors you might be navigating with your teen. It can feel hard to track, but these truly are all aspects of normal development. When you wonder what’s going on in their head, remember that sometimes it is literally about what’s going on in their brain, biologically speaking. A better understanding of your teen’s brain development can help you support their healthy development.

The dramatic development in a teen’s brain helps explain why parenting teens can be equal parts joy and exasperation. You might admire their creativity, fast learning, and adaptability, but you might still see them struggle with impulse control, decision-making, and evaluating consequences. Both the dizzy excitement and door slamming we see from teens can, in part, be explained by changes in the brain.

What is going on with my emotional teen’s brain?

A teen’s brain relies more on the emotional, reactive center, the amygdala, than an adult’s does. The area of the brain that controls reasoning and helps us think before we act, the prefrontal cortex, is still changing and maturing well into our 20s.

Compared to adults, the teen brain has a harder time thinking before acting or stopping action once it’s started. Their judgment can be overwhelmed by impulses, making it harder to choose between safer and riskier choices.

This doesn’t mean teens can’t show self-restraint or don’t know right from wrong, but they are partly driven by a brain that is currently relying heavily on emotional and reward-driven centers. That can lead to positives, such as strong social connections, and to challenges, such as reckless behavior.

Why is my teen obsessed with K-pop or video games?

There is increased activity in the part of the brain that heightens sensitivity to rewards in teens. The midbrain reward system is the area at the root of romantic love, habit formation, and the reward for being part of the pack. That system is still mostly in charge at this stage. 

Teens will be seeking social approval and exciting experiences. They’ll get immersed in listening to their favorite song (over and over) or want to try every new game. This reward-focused part of the brain can influence things like forming habits and addictions, but it can also lead to positive outcomes, such as joining peers in peaceful activism or volunteering.

Why is my teen so stressed out?

There are plenty of stress triggers at this age. Combine that with stronger emotional reactivity and still-developing coping systems, means that stressful situations can feel overwhelming. Teens may react more to stress more intensely than adults and also may be more susceptible to stress-related problems like anxiety and depression. There are hormonal changes at play that affect the limbic system and the neurotransmitter serotonin, which is important in mood regulation.

Why is my teen still asleep at noon?

This has biological roots too (they are also flexing their independence muscles). Teens are experiencing a shift in their circadian clocks, including changes in the sleep hormone melatonin, causing them to feel awake later at night and struggle with early mornings. Not getting enough sleep can further disrupt hormones and increase impulsivity and emotional volatility.

What helps teens, and their brains, thrive?

Amid all this change, adolescent brains are learning rapidly and have a great capacity for adaptation, called neuroplasticity. You’ll likely see them develop new skills and strengths, make social connections, and think in different ways. Even better, engaging in healthy, challenging activities can help strengthen those brain circuits and promote development.

Here are some things you can do to support your teen and their growing brain power:

Practice patience. What might seem like willful defiance, oversized emotions or thoughtless risk-taking can actually be about how their brains are wired at this age. You’ll still need to parent around those behaviors, but you can acknowledge the biological side while maintaining consistent expectations.

Prioritize good sleep habits. Sleep is essential for all of us. When possible, aim for a balanced schedule that aligns with their adolescent biology.

Be a coach. They are at an age where they are asserting their independence but still reliant on their caring families. Help them reflect on choices and consequences and coach them on different behaviors rather than criticize.

Help them cope with stress. It’s a good time to practice coping skills with your teen because, on the flip side of the brain changes associated with this age, teens also have a lot of cognitive flexibility, which allows them to adapt and shift their perspective more easily.

Seek support if needed. That applies to both you and your teen. Considering how dynamic the adolescent brain is during this period, it’s not a coincidence that major mental health conditions, including anxiety and depression, often appear during this time. If you’re worried about your teen or you need support yourself, talk to your provider, who can also refer you to mental health care. 

Links between the prefrontal cortex and the midbrain reward system develop over time and at different rates in different kids. While a teen’s brain reaches its largest physical size early in adolescence, it still has a lot of changes and development to do, well into their mid-20s. Have some patience and enjoy the ride. It’s an amazing thing to see your child become a teen, make new cognitive connections, become more emotionally aware, and find their own path.

 

About the Author

Susanna Block

Dr. Susanna Block, MD, MPH, is a pediatrician with Kaiser Permanente in Seattle and lives with her family in Queen Anne.