Teenager’s Brain

by on June 18, 2013

in Monthly

Inside the teenage brain: Science reveals why some are erratic, moody and impulsive

Adolescence is seen by some experts as a time when it is normal for a teenager to reject parents, choosing to be with friends instead, form their own values, experiment with all kinds of lifestyles and possibly become a temporary “disappointment.”

Q: My 15-year-old son is selfish, moody, impulsive, and at times I wonder why he makes silly decisions. I feel like asking him “What were you thinking?” but someone told me teenagers have immature brains. Is that true?
A: The adolescent years can be stormy, stressful, filled with strife, uncertainty, inconsistency, and frankly be quite unpleasant. Some have said that the teenage years are, by far, the most unpleasant stage of the family’s journey. Close to 2,300 years ago, Aristotle said “The young are heated by nature and drunken men by wine.”

Teachers, psychologists, social workers and counselors tell parents that they should relax and wait for this stage to pass and that somehow, the previously difficult teen will “settle down.” Adolescence is seen by these experts as a time when it is normal for a teenager to reject parents, choosing to be with friends instead, form their own values, experiment with all kinds of lifestyles and possibly become a temporary “disappointment.” (Not all teens go through this stage of mental turmoil, puzzling behaviour and drama.)

Between ages 14 to 24 humans are at great risk for accidents, addictions, brushes with the law, unprotected sex, suicide, depression, anxiety and death due to accidents.

If this is such a huge public health problem for society, could it be that there is an anatomical or physiological explanation?

It appears to be the case as researchers make new discoveries about the teenager’s brain. Dr. B.J. Casey from the Weil Cornell Medical College and the Sackler Institute in New York is a world-renown expert in sorting out how a teenager brain functions, or malfunctions at certain times.

Casey used three methods of scanning teenage brains: Structural MRIs which are used to measure the size and shape of structures; Diffusion Tensor Imaging which is used to study the connectivity of white matter fiber tracts and functional MRIs which tell researchers about patterns of brain activities.

The bottom line is this: although the brain reaches approximately 90 per cent of its adult size by age 6, the gray and white matter subcomponents of the brain continue to undergo dynamic changes throughout adolescence.

The amygdala matures during the mid teen years. It serves as an accelerator or gas pedal, and explains why teens seek thrills, drive fast, and take risks — especially when observed by peers. However, the brakes, the prefrontal cortex, which help with reasoning, planning and executive functioning matures much later, around 24 years. Brain maturation starts in the back of the brain and moves toward the front, thus explaining why the front matures last.

As these structures mature, they get pruned in a very complex and variable manner. Not only are we talking about anatomy, but also about neurotransmitters such as dopamine and oxitocyn which are involved in thrill seeking and sensing immediate, intense pleasure.

In a landmark paper published in The Annals of the NY Acad Science, March 2008, Casey concludes that her fMRI findings will have significant implications for heated debates on public policy and the treatment of minors in the judicial system. Adolescents show adult levels of intellectual capability earlier than they show evidence of adult levels of impulse control — especially in emotionally charged situations that require appropriate decisions in the heat of the moment.

This discrepancy between the maturation of the amygdala (gas pedal) and the prefrontal cortex (brakes) explains why teens are driven by pleasure, excitement, novel ways of thrill-seeking, speed, risk taking rather than being driven by weighing logical consequences.

One parent tells a story about a teen caught by police for speeding over 140 km per hour — far above the posted speed limit. The teen explained that although he knew that speeding was wrong and had the potential to kill himself or another person, he disagreed with the police calling him reckless. He felt he was concentrating all that time; he was in fact careful and paying close attention.

Less serious than accidents, homicide, unwanted pregnancies and drug addictions is a teen who switches from being an innocent, pleasant and kind child to an individual who one day tells the parents that their values are useless to him. Such a teen may reject the parent’s faith, prefer to be with peers far more often than family, and can oscillate between being nice one day and mean the next.

Compounding it all, the teen may exhibit moodiness, tiredness and the use of foul language.

Again, it relates in part, to that teen’s erratic brain maturation. Peers provide new thrills; parents are boring. Peers provide social validation; parents nag.

For parents who are hurting when this happens and parents who are puzzled by the inconsistencies in the teen’s behavior or parents who blame themselves, I suggest a heavy dose of patience, but also the wisdom contained in Dr. Gary Chapman’s book, The 5 Love Languages of Teenagers.

Dr. Peter Nieman has been a community pediatrician since 1987. he is the father of 4 children (three are teenagers) Dr. Nieman hosts www.drnieman.com and is a bi-weekly contributor to CTV Morning Live and a former contributor to QR77.

Comments on this entry are closed.

Previous post:

Next post: