3.Jay Giedd — Direct/Cross

JAY GIEDD: Jay Giedd, first name J-A-Y, last name G-I-E-D-D.

JAY GIEDD: Correct.

JAY GIEDD: At the University of California San Diego.

JAY GIEDD: Since August of 2014, so eight months.

JAY GIEDD: Since 1991 I'd been at the National Institute of Health, chief of brain imaging in the child psychiatry branch.

JAY GIEDD: Yes.

JAY GIEDD: Until August of 2014.

JAY GIEDD: It allowed me to expand the scope of my research into -- in addition to the institutes here in Boston, it's one of the centers for people who study brain development; the people, the technologies and support for my work to have a greater impact. So I liked my years at NIH a lot, so it was a difficult decision, but it turned out to be the right one for me.

JAY GIEDD: Correct. National Institutes of Health, and then a subset of that is the National Institute of Mental Health.

JAY GIEDD: I grew up in North Dakota and went to college and medical school there. My undergraduate degrees were in mathematics, then philosophy, then the natural sciences, biology, chemistry, physics. After medical school, I did psychiatric training at the Menninger Foundation in Topeka, Kansas, which was an old-school psychoanalytic model; and then Barrow Neurologic Institute in Arizona; and then I went to Duke University and did geriatric and child and adolescent psychiatry training.

JAY GIEDD: Yeah. It's a little unusual to be boarded in both geriatric and child, but they have more in common than people think, sort of the riddle of the Sphinx where people lock on four and then two, then three. So there's this idea of last in, first out or a palindromic that a lot of the changes in early brain development are undone in aging. And so they're not opposites; they're actually quite similar issues about how the brain changes over time.

JAY GIEDD: Yes, but predominantly child and mostly adolescents, just the nature of the studies. We followed people from young ages and had them come to my lab every two years. We took a picture of their brain. We got their DNA from their blood or their saliva or their skin. And we ask questions how they're doing at home, at school, at work. And so many of the people in the study then matured through the second decade of life, and that became key because that's when most mental illnesses emerge. Not all of them, not Alzheimer's, not autism, ADHD, but schizophrenia, bipolar disorder, eating disorder, substance abuse, panic attacks, bipolar disorder. So over half of all of the illnesses that emerge, emerge during the second decade.

JAY GIEDD: Yeah, I'm a practicing psychiatrist, but most of my time is spent with research, and most of it related to brain imaging, genetics and behavior.

JAY GIEDD: Oh, just for medical certification, you can -- after psychiatry, you can then develop a subspecialty with extra training in different areas. And one of the areas is geriatric, and another one is child and adolescent psychiatry. So it's doing additional training in those age groups.

JAY GIEDD: Yes.

JAY GIEDD: Over 300 papers, but the type of work I do is team science, so a lot of people contributed to those efforts, then papers with over 500 people from 80 different institutions. So a lot of papers, but most of them as part of a team.

JAY GIEDD: Toward the second decade of the research, since we started young and then as people aged, a lot became that. About half is healthy children and youth, and the other half was for illnesses such as schizophrenia, autism, ADHD, but 30 different groups. And both my work and my writing is almost exactly half and half, half healthy and half illnesses.

JAY GIEDD: Yeah. Some of the -- along the way then I became an adjunct professor in the department of family and reproductive medicine at Johns Hopkins. And one of the themes there was unwanted teen pregnancy. So that's not an illness, but it still has a huge impact on the lives of youth and their families. And so much of what I did I realize wasn't technically an illness, but it was still a huge impact, life decisions, people's decisions about careers, relationships, education, military service. And so it's kind of an odd area that is not technically an illness, it's not covered by medical insurance plans, but for adolescents it still has a huge impact on their lives.

JAY GIEDD: Yes.

JAY GIEDD: Yes.

JAY GIEDD: So it is what I do a lot of, but it's a bit mushy to define precisely. It starts in biology with puberty, and it ends in society in terms of being an adult role in society. So both the start and the end are imprecise because puberty can be anywhere between nine and 15 and still normal, and when we attain independent adult role in society, there's also a moving target. So people are waiting longer to get married, to start families, to buy a house, to start families. So it's a little bit imprecise in its onset and closure, but the idea is when we become from child into an independent functioning adult.

JAY GIEDD: Yes, we have, largely because of technology like brain imaging but also genetics and other areas. One of the odd parts about brain maturation -- so when you talk about adolescents, sort of the brain being mature enough to not need protection from that person's decisions, society's been -- has reached almost no consensus. So the age of reason in Catholicism is eight when you can be held accountable, morally, for your actions; to be -- a consent to sex is 13, depending on which state; to be married, 15; driving, 16; 18 to vote, to buy cigarettes or be drafted; 21 for a governor; 25 for House of Representatives; 30 for Senate; 35 for President. It's all over the place in terms of the consensus of, you know, when is the brain, quote, "mature." And so a lot of the work has been trying to have neuroscience help inform this gray area.

JAY GIEDD: Yes. Yes.

JAY GIEDD: Well, when we started these studies, we kind of wondered, should we follow people till 16 or 18, because I'm out of -- adolescent psychiatrist, by 16, people are already winning medals in the Olympics; that they're quite smart and mature and skilled. And even concern that it was only because of the Industrial Revolution that we've sort of stretched out this whole adolescence. So the first surprise was that it wasn't 16 or 18 but more like 25 to 30 when the brain was still having very active, dynamic changes. And this just wasn't even on our radar screen. We looked more closely, and things like if you go to the airport to rent a car, you have to be 25 or else the rates are extraordinarily high. And so with that -- this is the trouble in neuroscience that Hertz has all the best neuroscientists and we couldn't make progress. But this later became called the paradox of adolescence. So you should be at the top of your game, your resistance to cancer, tolerance for heat and cold, agility, physical acuity, so many things you measure you're absolutely at the top of your game. But morbidity and mortality go up 300 percent during this time. And so it was puzzling in terms of why, when we're so at our peak physically, that we have all of these concerns related to decision-making. Predominantly motor-vehicle accidents is the number one cause of death for teens; suicide or homicide are two and three, depending on how people characterize the events. But all of the top 10 seem to be related to these kind of brain maturation functions.

JAY GIEDD: That surprised us at first. So by age six, the brain is already 93 percent of adult size. And at first, that was very disappointing because we were going to watch how the brain grew as we got smarter. So it's this big, we can do arithmetic; this big, algebra; this big, calculus. And so when we realized that the size of the brain was so close to its maximum so young, it was a bit disappointing. And that still remains the case. The brain is as big as it's going to get by about 12, and actually becomes smaller after that. So it's like Michelangelo's David emerging from the granite, that we specialize the brain by actually making it smaller. We eliminate unused connections or connections that lead to bad things.

JAY GIEDD: So we used to think we'd point to a part of the brain, and so this part of the brain does X, and this part of the brain is for memory, and this part of the brain is for looking to the future. And that's been one of the changes. So now we see different parts of the brain are more like letters of the alphabet. And by about eight months, we have all of the letters in place. What happens as we go from child to teenager to adult through life, those letters get formed into words, the words into sentences, the sentences into paragraphs. So that's how the brain matures, but -- by becoming more connected within itself, but not by growing larger.

JAY GIEDD: Yes. Yeah, there's a process called myelination, which is where the nerves are wrapped in insulation, just like a copper wire. It's wrapped with that rubber coating to make the information go faster. And so throughout life into the fifth decade for women and the fourth for men, we get more and more of this insulation, which makes our brain move 100 times faster than without the insulation, and it's ready to refire again 30 times faster. So it's really responsible for what, you know, makes human thoughts much better than other species. So all throughout adolescence, we have this kind of one-two process of connections that we use become stronger and faster, and the connections that we don't use, they're not just sort of like lying there idle. They're physically removed from the brain. So growing up in North Dakota, it's a very good place to drive or to be a pilot because, from the sky, everything is like a checkerboard. It's all quarter-mile grids. You can get to anyplace on the gravel roads by turning. But as the roads become more used, they become paved between the major grain centers. They might have become multi-lane highways. So now you can zoom down those lanes, but you can't turn off every quarter of a mile anymore. You have to wait for the exits.

JAY GIEDD: Yeah. As these changes happen, as you get this insulating material that speeds everything up. Then you pay a price for that and that the brain is not as changeable anymore. So it's this balance of the brain staying changeable but also that we get better and better at what we ask our brain to do.

JAY GIEDD: So different parts of the brain reach adult status different times. The parts of the brain that keeps us alive, like heart rate, breathing, that has to happen very early, even in the womb. And then our five senses of sight, sound, touch, smell and taste, then those parts -- those connections get formed. And there's this sort of cascade, then, in terms of during the teen years when we have the parts of our brain involved in thinking about the future, making decisions, long-range planning, social interactions. They're the ones that are still under construction.

JAY GIEDD: Yeah, it's really the key to humans in terms of -- the biology creates a very broad range of possibilities. And as we go through the teen years, then our brains can become adapted to live in the North Pole or the Equator, anywhere between -- we can even live in outer space for a little while with the technologies that our brains have developed. And so this is the fundamental tradeoff. Our brains stay changeable way longer than any other species, and that's what allowed us to survive. Even compared to Neanderthals who we coexisted with, their brains were 10 percent larger than ours, but their brains matured earlier. So by 12, Neanderthals were already having their own children, were living with their children in caves. So what happened in humans was that everybody's ancestors in this room had adolescence whose brains were very changeable. And what predicts the big change in the brain wasn't how harsh the climate was but how rapidly the climate changed. And this became the key to our survival as a species.

JAY GIEDD: Yeah, it can be an activity, a skill, music, a sport, learning -- a knowledge about a certain area, almost anything physical or mental that we can imagine, the more we do it, our brain will become specialized and optimized to do that.

JAY GIEDD: It will be able to do those tasks with less energy, with less utilization of blood sugar and other energy sources. It becomes more streamlined. We can accomplish those tasks faster and more efficiently. But the price we pay is then we can't learn other tasks as easily.

JAY GIEDD: Correct.

JAY GIEDD: It's -- you know, partly because this is a time -- in terms of whether it's football or music or academics or other things, this is a key time in developing these skills so that -- even younger for certain things, between ages seven-11 is the key time to be doing piano, fine motor skills in terms of certain sports and certain abilities. But during the second decade, one of the key aspects is social because the main task is to stay alive and to reproduce, and so this is a time where there's a lot of social bonding, team sports, learning new skills.

JAY GIEDD: So the part shown here in green is the part --

JAY GIEDD: (Witness complies.)

JAY GIEDD: Okay. So, yeah, this is the part of the brain -- it's called the prefrontal cortex or the frontal part of the brain, and it's what's most different between us and chimpanzees or other genetic cousins. And it's the part of the brain that is for doing, in a sense, the hard stuff. And so that we have to wait longer for rewards, it controls impulses. It's involved in choosing the larger, later reward versus the sooner, smaller. And it's the part of the brain that allows us to do time travel.

JAY GIEDD: Mental time travel. So we don't have to just consider what's happening at the very present moment, like most animals; we can consider all of our memories, all of the experiences that we've had in our life, all of the input coming in through our eyes and our skin and our nose and our mouth but also our hopes and dreams for the future and to tie it all together. So going back to the letter metaphor, this would be where the paragraphs are formed, and it's the part of the brain that is latest to mature. So not --

JAY GIEDD: Yes, and to get along with each other socially and to run these different scenarios in our mind instead of the real world, so we can imagine different consequences and different actions instead of having to physically put ourself in harm's way. Again, this sort of long development is not necessarily a bad thing. It also then allows us to specialize in these different areas. But as opposed to the, you know, 25 or so parts of the brain, the purple parts, the limbic system --

JAY GIEDD: Yes. So these areas here, which are a collection of structures, they have a lot of hormone receptors. And so at puberty, there's drastic changes, not just in the size or the shape of them, but in the receptors and the density of different types of molecules. And there's an explosion, then, in the passions, in terms of sex drive kicks in, aggression, but also fundamentally rewards and punishments. So this -- puberty, if it happens around 12, that leaves a decade or more so in terms of balance that's changing. They're not really at odds with each other. The whole thinking was that the limbic system was sort of primitive and had to be overridden by the civilized, frontal lobe. Now it's seen much more as a dance between them. The limbic system tells us what our goals should be. It tells us our motivations. And the frontal part helps us achieve those goals. But inherently they're sort of at odds in terms of "Right now I see it, I want to do it, just let it happen," versus having the kind of stepping back and saying, "Let's think this through," what might be the longer-term consequences. And that balance shifts during the teen years.

JAY GIEDD: Yeah, it's emotional, but it's also -- it tells us what's important. So it's basically to stay alive and to reproduce, are the big ones, but also involved in even sleep, hunger, all of the drives that motivate us to do or not do things are related to the limbic system.

JAY GIEDD: Yeah, just to sort of -- so this is actually a movie, if it works as a movie, and it will loop around and around, but just to sort of focus on, again, this is that same area that I was mentioning, the prefrontal cortex, involved in controlling impulses, long-range planning, mental time travel, doing the hard stuff of what makes humans, humans. And what we'll see, if the movie runs, is when it turns blue, that's when it's reaching the adult levels, when it's maturing. And so this part of the brain is amongst the latest to reach adult levels.

JAY GIEDD: So if I was accurate with the circle, you can kind of see it's sort of like the blue will sort of circle the wagons. It will circle around and sort of close in on this area, indicating that it's very late to reach adult levels. It's not broken or absent in teens; it's just that it's not as good as it's going to get.

JAY GIEDD: Okay. Okay.

JAY GIEDD: Yeah, and, again, this is on average. So this is an average of 52 brain scans averaged across this age. So for a given person, they, you know, may be earlier or later on this process.

JAY GIEDD: Yeah, that's actually a really important point because when these studies -- when we say, you know, on average people -- there's so many exceptions to the rule, and so we have 14-year-old girls who are very future thinking and are not impulsive and long-range planning and 54-year-old men who never, you know, get to those stages. And so --

JAY GIEDD: I'm under oath, so I'll say yes. Yeah.

JAY GIEDD: And there's just a huge variation. That's been one of the biggest challenges of why we can't do very much with a single, individual scan. So everything I'm saying relates more to child adolescence and adulthood in general. There's many exceptions to the rules.

JAY GIEDD: The circle moves, so let me see if I can.

JAY GIEDD: (Indicating.) And so, again, it's not that before this age that it's defective or damaged or nonexistent. But it's just that it's not as good as it's going to get. It's still under construction. But in general, that's a good thing. It allows the brain to keep options open. So during these times we can specialize in all kinds of different things. It's a great time for learning. It's a great time for interventions. So I don't want to paint this as a bad thing or a pathology. It's a healthy part of humans.

JAY GIEDD: It worked, yeah. I guess that's a better way to say it, that it's both the blessing and curse of much of my work in terms of this plasticity creates the vulnerabilities to the illnesses, but it also creates the positives. And it's a double-edged sword.

JAY GIEDD: Yes. So the blue would be areas that are already at the adult level at these young ages. So here is -- this is called the sensory and motor strip in terms of this is basic sense of touch and of movement. At quite young ages, that's already at adult levels, visual centers, auditory also, you know, quite early. This part of the brain is involved in social interactions, in assessing what other people are thinking or feeling, affected in things like autism. But this is the key area involved in the things that make us most human in terms of our individuality.

JAY GIEDD: It's maturing throughout -- you know, throughout life we always have a reward system, but at puberty it really gets intensified, and so -- and it's literally puberty. So the frontal lobe, whether -- it's more your age, whether you're pre puberty or post puberty, the hormones don't affect the frontal part as much. But the limbic system is very hormonally sensitive, and so when that's activated, it changes our motivations; it changes our passions, again, for both -- you know, for good and ill; whereas the prefrontal cortex is sort of plugging along at its own -- at its own pace.

JAY GIEDD: Somewhere between 25 and 30. And, again, for a given person, it might be quite -- quite different than that. The brain never stops changing from conception, you know, through death. So sometimes we ask -- we're asked when does the brain stop maturing, when does it stop changing, and it's a difficult thing to answer, but in this context we're saying the brain increases -- more cells, more connections than can possibly survive, and then it prunes down based on our experience, and then it sort of levels off. And so what I'm talking about is this kind of leveling-off process, where things sort of slow down, and that's between 25 and 30.

JAY GIEDD: Well, teens are more likely to choose the smaller, sooner rewards, less worried about longer-term consequences, you know, 20 years down the road. Again, it may be a reasonable thing for, you know, teens to think that way. It's a time when they have greater reward seeking -- and this isn't even just humans. All mammals, all social mammals, have these huge changes in sensation seeking, reward sensitivity and a move away from parents to peers. And so this -- these changes are triggered by these limbic changes. And we're not going to make them go away. They're sort of part of our human condition. They're part of like even other species. And so the idea is to keep these non-lethal, in terms of -- car accidents is one example, but substances of abuse, things we didn't have when our brains were evolving, but now it's kind of a Stone Age brain with modern Computer Age temptations. But these changes affect and suggest a lot of decisions that teens make, many of which are quite rational, you know, in terms of for where the teens are at that moment in their life.

JAY GIEDD: It's tricky in terms of at some, you know, point we have to draw the line and we have to realize that for a given person that number is quite different. So I think in terms of 25, maybe, you know, being as good as it's going to get or close to that, but at earlier ages it might, you know, be good enough. It's a tricky line to draw, especially given that it's so different from person to person. But for certain decisions, in terms of financial planning and things like that, where there is a right answer, it's not even 25. People actually make better decisions well into their 50s in certain types of decisions.

JAY GIEDD: Well, on average, puberty 12, and then the end point 25, so it's sort of about halfway, actually. Yeah.

JAY GIEDD: Yes. Yes, on average.

JAY GIEDD: Yeah, so that's a big part of the research. The first, really, 13 years of my research was just creating the maps, what is the path of brain development. And then in 2002, we started looking at what matters, what helps it, what hurts it in terms of what are the influences that sports or music, bacteria, viruses, diet, schools, second languages, video games -- all these different choices. And so one of the ways to address this is to look at twins, identical twins versus non-identical twins. And what was striking was how big the impact of the environment is. And so the environment is not just sort of the pollutants in the air but family, friends, the media, all the non-genetic influences. And one way to think about it is that the genes are like the lightbulbs on a scoreboard, a huge scoreboard with a billion lights. So we're born -- we might have slightly different numbers of lightbulbs or slightly different arrangements, but what really matters is which lightbulbs are turned on and at what time. That spells out the letters; that spells out, you know, the numbers. And so the genetics really just sort of creates a very broad playing field, but it's the environment, then, that determines which of the genes are turned on in which sequences, and so we become, you know, much more impressed, I guess, with the potential for the environment to change the brain.

JAY GIEDD: Well, different environments have different impacts at different ages in different parts of the brain. But particularly during the -- after puberty and before adulthood, the big thing is social, that we stay alive by being part of a team, by being part of a group. We're not the biggest, strongest, or fastest. So it's really -- it's not algebra; it's not the things you learn in school. It's social, you know, fitting into social groups. And the way that the brain does that is through modeling, you know, not modeling kind of stuff but learning, and learning by example. So reading's only about 5,000 years old. Through most of humanity, nobody read a single word. Our brains learn by example, from our parents or family when we're younger, from peers when we're older, you know, or media. But the brain is really good at learning by example. And, you know, family is the proximate example. And sometimes I'm asked sort of what do I do different as a parent based on the brain science, and it's hard because it's not a long list. But one of the aspects is that we're always on. We're teaching our children about how to deal with emotions, about time management, about goals and values, not when we're having these big-day talks and, you know, sitting down. It's everyday moments, what we say about them when they're in the back of the car to other people. And so the idea, you know, in terms of this is when their brain -- because it's specializing, because it's eliminating connections and not, this is when we become who we are in terms of our values, identity, you know, what makes us unique individuals.

JAY GIEDD: Yeah, at the end of the day, we, you know, kind of go around and around and talk about when you become independent adults. And, pragmatically, we often kind of then come back to the second decade, you know, ten to 20, but more so because of -- like, it depends on the question being asked. But the data is available for the United States, Germany and Japan. Even since the 1970s, we're getting married five years later. We're starting families five years later. We're leaving home, you know, later. 30 percent of college graduates live back at home for at least a year. Not that that's inherently a bad thing, but biology hasn't changed in 40, 50 years. And so the whole notion of adolescence is -- always comes back to for what -- you know, it depends, and for what reason do you want to refine it. It's really hard to deal with the individual variation in terms of how different people are on this scale of maturation.

JAY GIEDD: It's hard to pick one, but I think that one of them is just that itself, how -- how protracted it is, how stretched out the ability of the brain to change. And the second is the changeability, that even, you know, all the other -- for instance, we're kind of amazed at how changeable the brain is, how good it is at adapting to the challenge of the environment. And it used to be thought at a pretty young age, you know, five or six, these things -- you know, give me a top age five, I can make him -- pre-scholar kinds of things, and that's just biologically wrong, which is very optimistic for people in my business, that from the biology standpoint, the brain is very changeable, you know, through, you know, much of a life, certainly the first three decades.

JAY GIEDD: Yes. I think a work in progress but not a damaged or defective brain.

JAY GIEDD: Good morning.

JAY GIEDD: Yes.

JAY GIEDD: Yes.

JAY GIEDD: Not only "as well"; predominantly, I think.

JAY GIEDD: Yes. But the behavior is the more direct observation.

JAY GIEDD: Even with -- even with the metrics, yes.

JAY GIEDD: Yeah, 20, 25 years.

JAY GIEDD: Correct.

JAY GIEDD: Correct. Which turned out not to hold up, but --

JAY GIEDD: Correct.

JAY GIEDD: I'm not sure I understand the question.

JAY GIEDD: Yes.

JAY GIEDD: Correct.

JAY GIEDD: Correct.

JAY GIEDD: Yes. Yes.

JAY GIEDD: Exactly. Yeah.

JAY GIEDD: Yes.

JAY GIEDD: Yes. Just to elaborate on that a bit, so the question was, "Is this 12-year-old impulsive? Can you do a brain scan to prove it?" And I said, "Well, he just, you know, jumped in a police car and took off. He's impulsive." That's the thing. The brain scan would, you know, not be any more certain than that. It would be more colorful and, you know, more aesthetic, probably. But to me it's backwards, that the brain images are only a loose indication of possible behaviors, but the behavior itself is --

JAY GIEDD: -- is the key, correct.

JAY GIEDD: Yes.

JAY GIEDD: Yes.

JAY GIEDD: Correct.

JAY GIEDD: And out of court.

JAY GIEDD: I stand by them, yes.

JAY GIEDD: Correct.

JAY GIEDD: Correct.

JAY GIEDD: Ah, yes. Yes.

JAY GIEDD: And we haven't, you know, met that challenge.

JAY GIEDD: Yes. I think that being able to get to the individual level is one of the big -- the big goals, but I think we're farther away from it than people realize. So one of the examples is to say that men are taller than women, so statistically that's true. If you take 100 men on average, 100 women on average, the men will be taller. The effect of that size is about twice as big as the brain-imaging differences. And so if you were to just look around the room and say -- if we went into a high school and said, "Everybody above five six, this locker room; everybody below, this other locker room," well, that's ridiculous. Why? Well, there's -- there's too many exceptions to the rule, just looking at it. And so that's twice the difference of the brain imaging. So I think that's, you know, a key point to make in terms of it would be very hard to go from a brain scan of a person and predict how mature, impulsive. So it's only with group averages that, even if the 14-year-old is mature, they're going to get even more mature, you know, as that individual goes through life. That's -- that's pretty strong in terms of that people get better and better at choosing the larger, later reward as -- as they mature. But it only holds at this group level. To say, like in 25-year-olds, as a group, we'll make decisions differently than 16-year-olds as a group, but that would be as far as I could push the science.

JAY GIEDD: Yes. I mean, there's many aspects of maturity and huge individual variation. If that's what you mean, I agree.

JAY GIEDD: Correct.

JAY GIEDD: Correct. But on average, people, you know, will get more life experiences, they'll make better decisions, they'll be able to control impulses better. Like you said, you know, not everybody, but that's a pretty strong direction as well, like most people, you know, will move in that direction unless they have, you know, damage to their brain or other things. Illnesses --

JAY GIEDD: I'm sorry. Or -- or people may develop an illness, such as schizophrenia or bipolar disorder, that might, you know, affect decision-making and such. But in health, that most people will progress on that dimension.

JAY GIEDD: Correct. Even -- even younger, I would say, as well.

JAY GIEDD: Even younger than -- than 19 years.

JAY GIEDD: But even younger, below age ten, in the right settings, they can, you know, do quite well with planning and consequences.

JAY GIEDD: Yes.

JAY GIEDD: Yeah, the context for that was the Internet, and that the amount of time spent with violent video games from 2002 to that time went up four-fold, but the degree of violence is only limited by, you know, our imagination. Coming across sexual content, it's almost impossible not to, just in the ads and such. So one would have anticipated, you know, this would be unraveling the moral fabric of our nation and such. But all of the statistics -- unwanted teen pregnancies, sexually transmitted disease, all the indices, 49-year low. Real world, you know, violence, 47-year lows. It was more of a puzzlement to us because if it had been the opposite, we would have been all over the cause.

JAY GIEDD: Uh-huh. I remember.

JAY GIEDD: It pains me to say that as an educator, but yes.

JAY GIEDD: Well, I mean, brain science is a very humbling business in terms of -- had it since I can remember, and, yeah, I think we're just scratching the surface.

JAY GIEDD: Durston or --

JAY GIEDD: Oh, me and -- okay.

JAY GIEDD: As a concrete example, so we have two ten-year-old, totally healthy, doing-great boys in the study whose brains are -- twice -- one's twice as big as the other, and both doing -- doing fine.

JAY GIEDD: So one of the goals when I started was to be able to do a brain scan to see if somebody had autism or ADHD or schizophrenia, and 25 years later, no. So that, as you indicated, we go to the behavior. That's the -- the gold standard in terms of these things. And so we're not -- we're not close, frankly. We're not right around the corner; you know, that it's going to be hard for a while. We'll have to actually talk to people. We'll actually have to understand behaviors. The, I guess, utility of it has been sort of these trends that, you know, in aggregate, the brain is incredibly changeable during the second decade, and it -- the development, the way we usually think of it, is protracted, in that the brain stays that way, you know, longer than any of us, I think, thought at the beginning.

JAY GIEDD: You know, I guess ready for prime time in the sense of -- so as a -- as a psychiatrist, if someone comes to see me, do I get a brain scan? No. I listen to them. I hear their family, their story. And I'd be the first in line if that, you know, wasn't the case. And, yeah, I think that we have to be careful about the colors in terms of --

JAY GIEDD: Yeah.