The neural pathways in the brains of children are small and incredibly interconnected, allowing them to learn new things very quickly, but around the age of 13 these small roads are consolidated into superhighways.

Question: Do psychotropic drugs affect adults and children differently?

Harold Koplewicz: So it’s unclear, but there’s no doubt that brains of children versus teenagers versus adults are different.  And I think it’s important for us to remember that your brain is truly a work in progress.  And that when you’re a child, your ability to learn things is quite remarkable and there is a plasticity to your brain so that if you want to learn to speak Italian, you will learn to speak Italian at 10 or 11 with as natural an accent as someone who has grown up in Rome.  And yet if you learn to speak Italian after the age of 13 or 14, you could learn the vocabulary and you can certainly learn the grammar, but your accent won’t be nearly as natural, especially even if you learned it at 40 or 50, where it becomes very trying for you brain to learn that new language.  

So essentially what happens is that at 13 your brain essentially says: "We have to become more efficient."  It’s very bushy out there, you know, every—there’s so many little roads and making little connections between different parts of your brain that aren’t being used, the brain essentially says, if you haven’t used it, we’re going to lose it.  So if you haven’t used that little country road, let’s say, the circuitous little route to learn to play golf, or to learn to speak Italian, we’re going to eliminate that.  And we’re going to create structured superhighways in our brain for learning.  

So in eighth and ninth grade, our subject matter becomes much more comprehensive.  We are able to learn so much more.  Now, that doesn’t mean that you cannot learn Italian or to play golf, but it becomes much more of an intellectual or cognitive experience.  So if you stop playing golf for six months the next time you go out on the course you have to remember what it is that I’m supposed to do.  How is it I’m supposed to hold the club?  What is it I’m supposed to do when I swing through versus, if you learned early in life and you stopped, you just have a natural swing.  You get back on the course.

And if you look at great Olympic athletes, they all learned to do their sports very early on. Four, five, six, seven—certainly before 13.  So at 13, your brain is becoming more efficient and that efficiency really, and renovation takes until you are 25 years old.  And it’s during that time of restructuring and renovation that serious psychiatric illness occurs.  So whether it is the first bouts of depression at 13 or 14, or schizophrenia at 18 or 19, or manic depressive illness or true adult bipolar disorder at 19 or 20, all those things occur when the brain is under this reconstruction or this renovation.  

So quite clearly, the effects of medication on a child versus an adolescent versus an adult are very different.  And very often, children will need lower doses.  Children will be more sensitive to the medicine than a teenager or an adult.

Recorded  August 18, 2010

Interviewed by Max Miller