Understanding the Teenage Brain

A Note From the L.A. Teen Therapist

Here is some important information that describes the developmental changes that occur in teenager’s brains. – Sandra

  • Has your teen ever felt blue for no obvious reason?
  • Do they ever do things on impulse that they later regret?
  • Have they ever overreacted to a situation and later wondered why?

Adolescence is now starting at younger ages than in previous generations. The average age that girls go into adolescence is between 10 and 11, when they reach 17% body fat. Boys go into adolescence between 12 and 13.

Teenagers are going through a transitional time when the brain rewires itself for emotional attachment, reproduction, and ultimately the creation of a stable family structure. 

There can be a noticeable gap between intelligence and behavior during the teen years. We used to attribute this to the assault of a hormonal hurricane. There is actually a lot more going on in the different structures of the teenage brain that end up having long-term consequences.

The myelin sheathing, which insulates nerves, increases by 100% in teenagers. Myelin sheathing is responsible for the conduction of nerve impulses to the brain. As the nerves become twice as efficient, this feeds the intensity and speed of a person’s reaction, contributing to the experience of mood swings.

The teen years are also time of the lowest levels of Serotonin in the human brain during human life. Serotonin is the primary transmitter in the limbic system, having to do with morale and moods. Low serotonin levels create a state in which a teens are more susceptible to feeling stressed and overwhelmed.

The brain does not grow in an orderly fashion. It first over-produces a bunch of connections that go to new parts of the brain. Then, in the later teen years-around age 16 through the mid-20’s-it starts eliminating connections based on how frequently they are used. The connections that remain determine a person’s sense of identity.

Did you know that the teenage brain does not complete development until close to age 25? Yes, something called the pre-frontal cortex, which is responsible for impulse control and operates much like the CEO of a company, does not complete development until your mid-twenties, leaving teens vulnerable to impulsive behavior.

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