#264      28 min 31 sec
Hormones in a hurry: Uneasy passages through puberty and adolescence

Psychiatrist and adolescent health specialist, Prof George Patton, discusses why puberty -- especially early puberty -- and adolescence can be so tough, but how most of us survive the journey. Presented by Dr Dyani Lewis.

"Those parts of the brain that really are involved in that emotional
regulation develop really continuously through the adolescent years
through to the mid-20s. So in a sense there's a bit of a gap. Now that
gap probably allows that creativity and that flourishing cognitively
during these years but it does create this window of vulnerability for
these emotional and behavioural problems." -- Prof George Patton




Prof George Patton
Prof George Patton

George Patton is the Professor of Adolescent Health Research with the University of Melbourne. He is a Senior Principal Research Fellow with the National Health and Medical Research Council and has a clinical background in Child and Adolescent Psychiatry. He has had advisory and consultancy roles with the UN, World Health Organization, the World Bank and UNICEF around adolescent health and development.  He played a leading role in both the first and second Lancet Series in Adolescent Health. In Australia he has chaired advisory groups producing ‘A Picture of Australia’s Children’ and ‘Australia’s Young People: their health and well-being’ over the course of the past decade.   He has also had advisory roles to the Commonwealth Government around issues that include mental health policy, suicide prevention, alcohol and illicit substance abuse, well-being and its assessment in children and men’s health.

Credits

Host: Dr Dyani Lewis
Producers: Eric van Bemmel, Peter Clarke, Dyani Lewis
Audio Engineer: Gavin Nebauer
Voiceover: Nerissa Hannink
Series Creators: Kelvin Param & Eric van Bemmel

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VOICEOVER
Welcome to Up Close, the research talk show from the University of Melbourne, Australia. 

DYANI LEWIS
I'm Dyani Lewis. Thanks for joining us. Puberty and the period of adolescence that follows it mark what are probably the most awkward of our developmental transitions. It's a time we remember most vividly and sometimes cringe about years later. As well as the raging hormones, growth spurts and other physical changes, adolescents also need to navigate a bumpy social landscape where peer pressure reigns supreme. Adolescence is when we start to work out who we are as we muddle our way through to adulthood, but for some it's a time when we can lose our way, sometimes with consequences that stay with us for many years or even the rest of our lives. But what makes puberty so disruptive? What's going on biologically and what are the consequences for wellbeing, both during adolescence and into the future? On Up Close this episode George Patton, Professor of Adolescent Health Research at the University of Melbourne, joins us to discuss the physical and emotional challenges of this turbulent period of human development and how people going through this time of life can be supported by those around them. Welcome to Up Close George.

GEORGE PATTON
Thank you Dyani.

DYANI LEWIS
George, can you give us a definition of what puberty is biologically?

GEORGE PATTON
Well your introduction was a very nice one in the sense that it is a life-changing event where there's a whole lot happening. We've tended to think about puberty as being that phase of life in which an individual reaches reproductive maturity. So we think about the biological changes, raging hormones, we think about growth spurts, but it's actually a whole lot more than that. Marked changes in the way an individual begins to think about himself, herself in relation to the rest of the world; there are marked emotional changes that go with that. It's in fact a series, a cascade of hormonal changes that happens. It's not all about sexual and reproductive maturity. The first changes of puberty, they begin when children are in mid-primary school.

DYANI LEWIS
About age seven or so?

GEORGE PATTON
About the age of seven. The first changes are in fact changes in what's known as the hypothalamic–pituitary–adrenal axis. Now that's a big word but it's actually talking about changes in that system which is intimately involved in stress responses.

DYANI LEWIS
The hypothalamus is in the brain?

GEORGE PATTON
The hypothalamus is a really important control centre in the brain, the centre of control of the pubertal process, together with a whole lot of other things such as sleeping, eating.

DYANI LEWIS
Then the adrenal gland, that's down near the kidneys. Is that right?

GEORGE PATTON
That's exactly right. Just on top of the kidneys. It's a gland that secretes in this early phase of puberty what are known as adrenal androgens which are really important in the way an individual responds to stressors like responses to heat or cold or physical exertion, but it's also important in relation to emotional stressors.

DYANI LEWIS
I would have thought a process that leads to, like you said, reproductive maturity is going to involve the sex hormones more than these stress response hormones?

GEORGE PATTON
Well that comes a little bit later. We think that a year or two after this process known as adrenarche we get the switching on of that process that leads to sexual and reproductive maturity. That's a process called gonadarche. It occurs a little bit earlier in girls than it does in boys; typically in the Australian context you'd be talking of a process that begins at around the age of 10 or 11 years with breast budding in girls being the first obvious sign.It comes to a sort of completion with the onset of periods, which typically in the context of Australia and many other high income countries around the world is typically between the age of about 12 and 13 years.

DYANI LEWIS
So it's really a combination or a progression from these early stress hormone responses then moving onto the reproductive hormones afterwards?

GEORGE PATTON
That's exactly right. At around the same time as we're getting these changes in the reproductive hormones we are, in girls in particular, getting the growth spurt. One thing that is really quite different about puberty in girls as opposed to boys is that this growth spurt appears a year or two earlier in girls. That's why when you compare girls at about Year 8 in the school system, girls appear to be so much more mature than boys of a similar age.

DYANI LEWIS
So that's like age 12 or 13 or so there's lots of differences?

GEORGE PATTON
Around that age yes, 12, 13, 14. 

DYANI LEWIS
Not everyone goes through puberty at the same time so what sort of things can influence the timing of puberty?

GEORGE PATTON
Look, you're absolutely right. The timing of puberty, well firstly it's quite different now to what it was say a couple of hundred years ago. In the course of the last 150, 200 years we've probably lost about four or five years in terms of the age of onset of puberty. So if we go back to the best records that we have from Northern Europe, countries in Scandinavia for example, in the early 19th century girls would typically have first onset of periods between 16 and 17 years. Now it's between 12 and 13 years.

DYANI LEWIS
That's a huge difference and obviously in that time we can't expect that there's been a huge change in the genetics of the population?

GEORGE PATTON
No. We think that a really important change has been around early childhood infections and getting on top of those early childhood infections, and better nutrition. We know that bodyweight during childhood is one of the key factors that determines the timing of puberty, particularly in girls. Girls have to reach a certain percentage of fat compared to lean body mass before actually the whole process gets switched on.

DYANI LEWIS
So is this why kids or girls in particular that are doing things like gymnastics or athletics often have delayed puberty?

GEORGE PATTON
That's exactly right. That's probably mostly to do with their bodyweight, so they have a lower proportion of body fat compared to other girls of a similar age, but it may also be something to do with the high levels of physical activity as well which may be another influence.

DYANI LEWIS
Is there a particular cut-off age that defines what is early puberty?

GEORGE PATTON
You're absolutely right that within individuals or within a group of girls, say in Melbourne, Australia, there'll be a range of five to six years between the onset of puberty in the early onset group compared to the late onset group. What constitutes early puberty probably depends a little bit on where you were living and what your ethnic background is. So some of the best studies come out of North America. Black American girls for example have an earlier onset of puberty than white American girls. So typically in black American girls breast budding, that first sign of puberty, is at about the age of nine on average. In white American girls it's about 10. In European girls it's about 11. So it does depend a little bit on which country you're living in and if you're living in a country where you have quite a deal of disparity between rich and poor, say take a country like India where if you're a wealthy middle class girl your age of onset of puberty will be typically at around the same point as it would be in Melbourne, Australia. But if you're living in a poor rural setting it can be three or four years later.

DYANI LEWIS
So it sounds then like there are definitely environmental factors such as which country you're growing up in or what your nutritional status is but then there are also distinct genetic factors?

GEORGE PATTON
Absolutely right. We're learning quite a lot more about some of these factors that influence the timing of puberty. Genetics is really important. So if your parents went through puberty early you are more likely to go through puberty early. That's probably one of the clearest factors that we know to be associated with early puberty but there are other things in the environment that are really important. We talked about bodyweight during childhood. So children who are overweight are more likely to go into puberty early. If you are born premature or at low birth weight you're also more likely to go into puberty early. That may be something to do with some early life programming of a life course strategy in which, in terms of human evolution, it would be programming a life course strategy that was about early reproduction.

DYANI LEWIS
So for the kids who are entering puberty early, is it just the puberty that starts early or are some of their other developmental milestones also happening earlier like during infancy and those times?

GEORGE PATTON
When we think of puberty as part of a life course strategy it does look as if the kids who go into puberty early differ in other ways. Now some of those things are to do with the family background of these kids. So girls who go into early puberty are more likely to come from families where there is no biological father. We also know that girls who come from families where there's a background of a lot of family conflict, they are also more likely to go into puberty early. We're not sure why this is and what the mechanisms are but if we look at these kids as early as the age of four and we look at their emotional and behavioural profile, they tend to be a group of kids who are having greater difficulties with peers, fitting in with peers, tend to have more bullying during primary school, early primary school; they tend to have a lot more emotional and behavioural problems as early as four years, suggesting that there's something about the life course of these kids which is different.

DYANI LEWIS
There's increasing evidence that what parents do sometimes before conception or during pregnancy can greatly influence a child's development. Do some of these effects also play a role?

GEORGE PATTON
Well the best-known effects are the ones that I talked about, about what happens when a mother is pregnant. It looks as if those babies who fail to thrive in utero are more likely to go into puberty early and one of the best examples are kids who are adopted from low income settings where maternal nutrition during pregnancy and before is not particularly good where they're adopted into a high income setting. So these kids effectively have a double whammy in terms of risk for early onset of puberty because they have the risks from prior to birth and an in utero environment which is less than optimal, together with growing up as a child in a nutrition-rich country like Australia or the US where they have a risk for putting on quite a bit of weight.

DYANI LEWIS
But like you said, it kind of makes evolutionary sense?

GEORGE PATTON 
It makes absolute evolutionary sense in that there is - in some way the clock here that is determining the timing of puberty is taking into account whether or not a female in particular has the adequate nutritional resources on board in order to be able to move on to a phase of life that is about reproduction.

DYANI LEWIS
You're listening to Up Close. I'm Dyani Lewis and our guest today is adolescent health specialist, Professor George Patton. George, is there a difference between the term puberty and what that refers to versus the term adolescence and what that refers to?

GEORGE PATTON
This is an important distinction. So adolescence is that phase of life that begins with this biological event of puberty and all that goes with it but it ends with what have been transitions into parenthood, into marriage, and which in the modern world is also about things such as completion of education, moving into employment, becoming financially independent. That process of adolescence has changed markedly and in many parts of the world is still changing. For example adolescence in pre-industrial societies for girls lasted for about two years. That is the gap between the onset of periods and becoming a parent. For boys it was about four years. But that all began to change at around the time of the industrial revolution and kids have begun to spend longer and longer periods in education; the whole process was accelerated in the 1960s with the advent of effective contraception so that in a country like Australia the gap between reproductive maturity notionally at the age of menarche, 12 to 13 years, and having a first child is almost two decades. This is a profound change. This process of the changing shape of adolescence is something which is really continuing right across the world now so that even in low income settings the age at which girls and boys are marrying is creeping up and with that creeping up of the age of marriage we're seeing creeping up of the age of parenthood and we’re seeing a whole lot of other changes in relation to sexual health and sexual behaviour during the teens.

DYANI LEWIS
That period of adolescence is usually very tumultuous socially. How does this affect the mental health during adolescent years?

GEORGE PATTON
The adolescent years have long been viewed as a period of emotional turmoil and the first figures who described adolescence talked of it in those terms. The early psychoanalysts also talked about adolescence being a phase in which once again conflicts from earlier in life are again encountered and they cause emotional turmoil. Those ideas have changed and I think we've come to recognise that in terms of risks for the onset of mental disorders the adolescent years are really critical. We now believe that about 75 per cent of all adult mental disorders begin before the age of 25 and it's during the teen years where the highest risks are. So in terms of risks for mental disorders what happens in adolescence is central.

DYANI LEWIS
You've also looked at the psychological consequences of early puberty in particular. What kind of impact does early puberty have on these mental conditions?

GEORGE PATTON
What we do know is that those gonadal hormones, testosterone, oestrogens, these are biologically active at a brain level and they affect emotions. So as girls go through puberty there is a greater difficulty that they report with control of emotions. These can be emotions like anxiety, unhappiness, anger, knowing how to relax when you feel tense. These things change markedly and, with those changes, there is a risk for the onset of depressive and anxiety symptoms during these years.That happens whenever puberty occurs but the risks appear to be that much greater when puberty occurs earlier, possibly because those kids are less prepared for those changes.

DYANI LEWIS
So does this then mean that late puberty can be protective?

GEORGE PATTON
In girls there's good evidence that in terms of psychological wellbeing late puberty is actually a protective event.

DYANI LEWIS
What about for boys?

GEORGE PATTON
For boys it's a little bit more complex. For boys who mature earlier there probably are some advantages in terms of greater strength, greater height, for the boy in terms of his social standing within the peer group going into puberty earlier. So there's a little bit of evidence that it can work both ways in terms of boys. Having said that, boys who go into puberty early tend to have had a greater history if you like of behavioural and emotional problems during early childhood.

DYANI LEWIS
In terms of the long-term consequences, are there any for psychology or physically even?

GEORGE PATTON
There are some well-recognised risks that go with early puberty. For example cancers of the reproductive tract, testicular cancer, prostate cancer in males, breast cancer and ovarian cancer in females. These are linked to early puberty. So too in terms of risks for later obesity or Type 2 diabetes or even cardiovascular disease later in life, early puberty does appear to be associated with greater risks. In terms of emotional and behavioural problems, the studies haven't really been done at this point in time but it certainly does look as if during the adolescent years early puberty confers a heightened risk for things like depression and anxiety, things like substance use and abuse, things like socially and physically aggressive behaviour. These things are linked to pubertal development and kids who go through puberty early appear to have a higher likelihood of these problems during the adolescent years.

DYANI LEWIS
With all the turmoil that's going on in adolescents, how do you pick out the problems from just the ordinary run-of-the-mill kind of changes that are happening to everyone?

GEORGE PATTON
There have been some really interesting studies. One American study tracked kids from the age of nine through to 19 and asked the question how many develop a diagnosable mental disorder during those years, and the figure was about 80 per cent. It's almost like the common cold of adolescence to have a problem of this kind. Clearly not all of them persist. In work that we've done we find that at least a half of kids who have a single episode of emotional problems which a GP would be concerned about had no further problems during young adulthood. So clearly there is a process of recovery and that's a really optimistic message for parents and teachers who are working with young people. Many of these kids find strategies or maybe it's something to do with brain development during these years but they get better.

DYANI LEWIS
That is a very optimistic view. You're listening to Up Close. I'm Dyani Lewis and our guest today is adolescent health specialist, Professor George Patton. George, are some of the risky behaviours that adolescents engage in all to do with finding yourself as an individual and testing out new things or is there a biological explanation for it?

GEORGE PATTON
It's a really good question Dyani. One of the changes we haven't actually talked about is some of the changes in the systems, the biological systems that underpin social affiliation. So the oxytocin system is one of the hormonal systems in the brain that changes as kids go through puberty. I think any parent knows that what happens as a kid goes through puberty is that who becomes important is very different to who was important when they were younger children. So parents become not so cool; teachers also have a similar experience and the peer group and the external world becomes far more important. That's probably a biological change. Now we see that play out in terms of risks for substance abuse. So these are things like taking up smoking, binge drinking, using illicit drugs like cannabis. These are the kinds of things that are common risk behaviours in the Australian context. As kids pass through puberty the risks increase. So kids at later puberty are at higher risk of substance abuse at a similar age than kids who are at early puberty at that age. That's a very clear-cut finding and the evidence suggests that what is happening for those kids at later puberty is that they're viewing their social world in a different way. They're wanting to engage with the alpha plus peer group and, to the extent that you actually have an alpha plus peer group who are a group who are partying, substance-using kids, the kids at later puberty are taking on those values, those attitudes and those behaviours. That appears to be the mechanism. So it's a complex interplay between biology which is driving this differential social affiliation with the peers and what's happening in the social context.

DYANI LEWIS
What about the kids growing up in lower or middle income countries?

GEORGE PATTON
Well that's - almost 90 per cent of the world's adolescents actually live in lower and middle income countries. That's again one of the things which has changed profoundly in the last couple of decades in a whole range of ways. So some of those health risks that we recognise in countries like Australia, so things like substance use, tobacco use, obesity, lack of physical activity, sexual health risks in kids who are unmarried but sexually active, these are changes which we had thought were really problems of the high income world. They're now very much problems of the 90 per cent of adolescents living in lower and middle income countries. That's a big challenge. It's a challenge for health services for example in terms of how health services respond to these changing needs. So not so long ago, if you were talking about a country such as India, you would have been talking about a very traditional society where the sexual and reproductive health risks were those of young women who were marrying at an early age and having children at an early age. But if you're looking at countries such as India today, particularly in urban settings but also even in rural settings, we're seeing this change in the age of marriage - it's getting higher; we're seeing the rise in unmarried sexually active adolescents, their access to contraception, their access to treatment for sexually transmittable infections. These are the kinds of things that health services need to do differently. There's a fair bit of evidence, whether one's talking about India, whether one's talking about countries in Sub Saharan Africa, in Latin America, that health services are not making that transition well enough for adolescents; they're not providing the kind of accessible, non-stigmatising healthcare that adolescents need.

DYANI LEWIS
George, is there anything that parents and teachers or even the health system can do to try to make adolescence as smooth as possible?

GEORGE PATTON
We've talked a lot about the negative side of adolescence and there are some amazing positives. So I want to emphasise that the adolescent years are those years where an individual in terms of flexibility of thought, creativity, these are the years in which an individual peaks. From the age of 14 in a sense it's all downhill cognitively. So there are some real positives. But it is a very different world to the world in which Homo sapiens, human beings evolved. It's a world which is much more complex; there are more challenges; we've seen the advent of social networking and digital media which have really changed the shape of development. So I think many of us are thinking that we need to think well about the social scaffolding that we provide for young people during these years. Now the scaffolding is one that shouldn't in any way diminish or hamper that creativity, that amazing cognitive development that happens during these years, but it is one that provides support when it is needed, what the values are that are really important for an individual until he or she can develop those values and that capacity to regulate one's emotion and behaviour that happens in young adulthood but it isn't all there during the teen years.

DYANI LEWIS
In terms of regulating emotions though, is there a shortcut to working out how to do that or is it really just something that you have to wait to be old enough for that to kick in?

GEORGE PATTON
Those parts of the brain that really are involved in that emotional regulation develop really continuously through the adolescent years through to the mid-20s. So in a sense there's a bit of a gap. Now that gap is probably the gap that allows that creativity and that flourishing cognitively during these years but it does create this window of vulnerability for these emotional and behavioural problems. 

DYANI LEWIS
So George, as someone working in adolescent research, what are the burning questions that need to be answered into the future?

GEORGE PATTON
If you look at where the research has been, if you look where the emphasis in social policy has been, we've had a huge emphasis on the early years, so the first three years of life, and those are really, really important years of life. The adolescent years have been somewhat neglected and where the emphasis has been has been generally around specific problems in sexual and reproductive health. So HIV for example, around half of all HIV infections occur before the age of 25 and it's understandable that that's been an important focus. So too teen pregnancy has been a really important focus. But there are a whole range of health problems that also emerge during these years that have really seen very little attention. Injuries account for 40 per cent of deaths in this age group. These are problems related to emotional control to a large extent. That 40 per cent compares to about 12 per cent in other age groups and yet we really haven't seen adolescence front and centre of injury prevention strategies as we've needed to. Mental health is clearly another area where the great majority of mental health problems occur during these years and in Australia we have seen a real emphasis and advocacy around that area but we probably need to be doing more, particularly on the prevention side. Early intervention is good but prevention is even better and we've seen very little in that space. So too in terms of risks for later life cancer and cardiovascular disease. Many of those risks actually emerge during the teen years. Some of them are related to lifestyle, so tobacco use; obesity to a large extent emerges during these years; alcohol use, again a major risk factor for later life, non-communicable diseases. These emerge during these adolescent years. So too patterns of physical activity emerge during these years. Dietary habits. These are really important neglected areas that we haven't seen enough focus on. I think that we're likely to actually see these years actually as becoming more important in terms of the healthy start to life for the next generation because adolescents are the parents of tomorrow. In low income settings we've actually begun to see a recognition that the nutrition of mums for example in the pre-conception years is critically important in preventing infant mortality and childhood stunting. So in a sense we haven't seen the focus go back beyond the identification of pregnancy but these data would be saying look we actually need to be looking at the pre-conception years. So too in mental health problems that are really critically important, maternal depression. It looks as if much maternal depression really begins not after a child is born but actually in the pre-conception years. So in this way as well giving a child a healthy start to life probably means investment in that child's parent when they are adolescents.

DYANI LEWIS
George, thank you for being my guest today on Up Close. 

GEORGE PATTON
Thank you Dyani.

DYANI LEWIS
George Patton is Professor Adolescent Health Research at the University of Melbourne. Relevant links, a full transcript and more info on this episode can be found on our website. Up Close is a production of the University of Melbourne, Australia. This episode was recorded on 14 August 2013. Producers were Eric van Bemmel, Peter Clark and myself, Dr Dyani Lewis. Audio engineering by Gavin Nebauer. Up Close is created by Eric van Bemmel and Kelvin Param. Until next time, goodbye.


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