Improvements in nutrition, hygiene and control of infectious diseases are producing an epidemiological transition in which noncommunicable diseases, including chronic health conditions and disability, are emerging as major health problems in adolescents and young adults, not just in old adults. But to start with, what comes to mind when you think of an adolescent with a chronic health condition? What about an adolescent with a disability? Is it a physical or a mental health condition that's come to mind? Is the condition you've thought of visible or is it invisible? Many people may think of a physically disabled adolescent but there are many more young people with invisible disabilities to consider. Perceptions of both child and adolescent health and disability have changed dramatically over the past century, as have ideas about health and illness, medical developments and advances, threats to adolescent health and development and expectations for adult functioning. But, an important consideration here is terminology. Are we talking about physical or somatic diseases like asthma and diabetes? But what about depression? A mental health condition which can last for many months at a time but typically can be relapsing in course. Do you consider autism, a developed mental condition, in the same way that you might think of other chronic health conditions? And if not, why not? And how long does a condition need to last for it to be considered chronic? Is it three months? Might it be six months? 12 months? Or does it need to be expected to last forever? A definition that I like is this one here, as complex as it is, that a chronic health condition has a complex etiology with many factors leading to onset, has a lengthy developmental period in which symptoms fluctuate in severity and functional impact, has a prolonged course of illness in which other conditions or comorbidities may arise with associated impairment or disability. And what we can see from this definition is that all of those examples that I raised earlier could be considered chronic health conditions. But I can imagine a number of you may be sitting there wondering, how common are chronic health conditions in adolescence? And in this regard I'm afraid that the prevalence of chronic health conditions in adolescence is remarkably difficult to assess. Now one reason, and you've heard this before, is the lack of data that is categorised by appropriate age cuts, the adolescent and young adult age group, the teen to 24 year old age group. However, an additional problem, and perhaps it's just as big a problem actually, is due to the very wide range of different definitions of chronic health conditions that are used in different studies. Some for example use a six month, duration, some use 12 months others use only physical health conditions, others use a wide variety. Up until recently, the main focus of many studies was primarily physical or somatic conditions, and examples as I've listed here include asthma or type one diabetes, sickle cell anaemia, thalassemia, epilepsy, congenital heart disease. But even if we just focus on these conditions, definitions can still vary very widely between studies. Take the example of asthma and think of definitions which can vary from ever wheezing to ever diagnosed by a physician or doctor with many other possibilities in between which obviously, when you stop and think about it, have major implications on the population prevalence, or the frequency of asthma in adolescence. And do you include conditions that have say, correctable vision as a chronic health condition? Some studies do and others wouldn't. And what about obesity? Clearly, a significant physical health problem, but until relatively recently, obesity was thought of in the same way of overweight, more as a risk factor for future health rather than a chronic condition itself. But arguments can readily be made that obesity is not just a risk factor for other health conditions, but due to the extent of underlying inflammation can itself also be considered a chronic health condition. I've listed here examples of what we'd refer to as neurodevelopmental and mental health conditions. Others not listed here would include learning difficulties and the cognitive deficits that accompany acquired brain injuries that not uncommonly result from significant accidents and injuries. Sometimes these diagnosis are included in national surveys of disability, for example, but other times not. The international classification of functioning disability and health, a WHO definition, considers disability as an umbrella term for impairments at the level of the body, at the level of the person and at the level of the person in the context of their social situations. Disability here is the overarching term for impairments at the body level, for activity restrictions, at the personal level and participation restrictions at the level of the person in society. The International Classification of Functioning defines impairments as problems in body function or structures such, such as a significant deviation or loss. It defines activity limitations as difficulties an individual may have in executing a task. And it defines participation restrictions as problems an individual may experience in involvement in life situations. And we can see that these definitions of disability are much wider than have historically been considered to be a chronic health condition. And then we come to the last definition or way of thinking about chronic health conditions and that is young people with special healthcare needs. The def, definition of children and youth with special health care needs are those who have or are at risk of having a chronic physical, developmental, behavioural or emotional condition, and who also require health and related services of a type or amount beyond that required by children and young people generally. And as you can see with this definition, not dissimilar to the definition of disability that the ICF has used, rather than being diagnostically based, this is what we would refer to as a, a non-categorical approach. It's not disease specific. With the belief that there are commonalities that cross disease categories that are important. Obviously, there are individual issues that are specific to each particular disease or condition. But definitions like this one appreciate that perhaps, it's the commonalities that are more relevant to the lived experience for young people themselves, but also the lived experience of their families. And, as well I would argue, how professionals may need to engage with adolescents with special healthcare needs or disabilities and their families that has got a lot more in common, perhaps, than there are differences according to different conditions. So, what does all this mean? In trying to put this together and in integrating a very, very large number of surveys, it is clear that we are saying increased survival of children into adolescence, and then survival of adolescence into adulthood of children with complex chronic conditions which previously were either fatal in infancy, or early childhood, or early adolescence. Technical improvements in medical care when combined with better access to healthcare have resulted in very significant improvements in survival for this group of young people with even the most highly complex chronic health conditions, and this would include examples like congenital heart disease, cystic fibrosis, and diabetes mellitus. It's also useful to think of survivors of childhood cancer or adolescent cancer in this age group. Because cancer used to be considered an acute condition which, to put it crudely, you either died from or you didn't. Yet, it's now appreciated that survivors of cancer in adolescence commonly live with a number of related or consequential secondary chronic health conditions, that either result from the cancer treatment itself or its complications. And that require more frequent health monitoring, and that they're also at relatively high risk of second cancers developing. So, surviving cancer is now appreciated as living with a chronic health condition. But for other conditions, we have seen a true increase in incidence in many parts of the world. Examples in the high income world increases in the incidence of asthma, of anaphylaxis, and allergies, and type 1 diabetes. We are also seeing markedly increased prevalence of mental health and neuro-developmental disorders such as depression and anxiety, suicide, self-harm, eating disorders, learning difficulties, attention deficit hyperactivity disorder, and autism. Now, there is some debate about what proportion of this very large increase in prevalence is real and what proportion might be due to, if you like, a greater propensity or likelihood of diagnosing these conditions. But most people believe that there is little debate that at least part of this increase in the, the prevalence of mental health and neurodevelopmental conditions is indeed real. And, at the same time, we're seeing much larger cohorts of young people with previously very uncommon conditions. Now, an obvious example is obesity, which is increasingly as I mentioned before, considered a chronic health problem. Type 2 diabetes and the metabolic syndrome, common accompaniment or comorbidity of obesity in adults used to be very infrequently seen in adolescents, and sadly, this is no longer the case. And of course, there is HIV/AIDS, which antiretroviral treatment has successfully turned into a chronic health condition for many people living with this condition. Now, the figure here is from the United States and this shows the prevalence of children and adolescents with special health care needs by age. And you can see the increase from childhood into adolescence, with a further increase, not shown here, into young adulthood. And so, in pulling all of this together, in high income countries the prevalence rates for chronic health conditions in adolescents are up to, between about 30 to, believe it or not, 30 to 40%, if you include all conditions with about perhaps 4% to 5% of adolescents having severe complex chronic health conditions, all depends on how you define it. Now, for the last two slides, I want to turn firstly to the effects of having a chronic illness or disability on adolescent development, and then highlight the reverse, that is, the effects of adolescent development on chronic illness itself. In relationship to this, we don't have time to go into the detail of this today, but I just want to give a flavour of it, a some way of thinking about some of these issues that, no doubt online, you'll be engaged in thinking about in a different way. So, to start with you think of with chronic illness or disability and the effect that this has on adolescent development. What we do know is that children and young people with significant chronic physical health conditions can have dramatic interruptions, if you like, in their normative entry and pattern though, the normative trajectory through pubertal timing. Most commonly, this is when pubertal timing is delayed. And so, that young people are older at the age of their first menstrual period or menarche, and that they enter their growth spurt at an older age, if you like, out of sync with their healthier peers. For some young people with severe chronic health conditions, and examples would be chronic renal failure, they might end up with a short stature as adults. So, chronic illness itself can have profound impacts on the biology of normal pubertal development. But perhaps, just as potently are the impacts of chronic illness and disability on relationships with families and peers. We talk about young people living up to the expectations of those around them. And, one of the challenges for families where there are children and young people with chronic health conditions is that families typically can have reduced expectations of what these young people might achieve in they're lives. For some young people with disabilities which render them physically immobile, or who are more dependent on family for mobility or other asp, activities of daily living. This means, they can have greater reliance on their families. And, reduces their opportunities to, in a sense, move out into the bigger world, beyond the family, into their communities with, if you like, reduced opportunities for developing resilience. We know that the presence a chronic illness or disability pr, can profoundly effect young people's sense of self. Their identity, their sense of, belonging in the world, and renders them typically feeling quite different to otherwise healthy peers. And we only have to think about the challenge of identity for healthy young people, let alone for young people who are challenged by many of the accompaniments we've talked about in terms of the different sorts of chronic health conditions that young people can experience. And a particular example of the challenge of that is how, this might impact young people's perceptions of themselves as being sexually attractive. And in terms of adolescent development, which is about exploration of, relationships and growing intimacy One can see how this might be challenged, or more challenging for young people chronic health conditions. And then finally, I just wanted to touch on those notions of how chronic illness can impact on those social role transitions that we've talked about previously as denoting entry into adult life. So for young people who might have reduced mobility they can be, end up in quite socially isolated from their peers. This can result in them having greater difficulty in terms of establishing peer relationships and more intimate relationships and can also obviously greatly impact on the likelihood of them having the same level of education or the same opportunities as their otherwise healthy peers. So, one of the challenges here in a sense is that the impact of a chronic illness on, or disability on adolescent development can also result in the emergence of depression, which then of itself can have profound further impacts in terms of how young people are maturing In terms of further limiting their opportunities to, if you like, engage in the world in healthy ways. And then finally, what about the reverse of that, thinking about the affects of adolescent development itself, and how adolescent development might impact on or affect chronic illness itself. Again, let's think of the example here of biology. Earlier George talked about how the onset of puberty changes the timing or the trajectory, increases the likelihood of a whole range of, if you like, mental health outcome such as depression, anxiety, self harm, eating disorders. But the onset of puberty can in addition to these, the onset of puberty can also in striking ways effect the disease progression of physical health conditions. So for the example with type one diabetes. For adolescents with greater growth hormone at the time of, puberty. But this can have very significant repercussions in terms of metabolic control of diabetes, can make it much more difficult to achieve the same level of control as adolescents would have been able to achieve pre-puberty. And similarly in the ch, chronic severe physical health condition we refer to as cystic fibrosis that it is entry into puberty which is associated with what we refer to as dimorphic or gender differences In terms of heal, health outcomes with young men typically from the age of puberty having better respiratory health than young women. But just like the importance of adolescence in terms of the timing of onset of puberty, we also know that brain maturation matters greatly in terms of how young people are thinking about themselves and the significance of chronic illness. So with the great brain maturation that takes place in adolescence, young people often in early adolescence for the first time start to develop a more nuanced, or if you like, sophisticated way of thinking about some of the repercussions of the significant, or of the particular chronic illness that they might have. So for young people who actually have life-limiting or terminal chronic health conditions, before adolescence develops They typically do not have great inside or understanding about what this actually means, whereas it's in adolescence itself that the greater insight that young people gain suddenly then shifts the significance of this chronic illness because they're able to think about themselves into the future a little bit more than what they're able to do when they were younger. And not surprisingly, given what I talked of in the previous slide about increased rates of depression and anxiety simply being a feature of adolescence itself. Surprise, surprise, we see about double the rate of depression and anxiety in young people with chronic disease. As well as this though, that adolescent development can also have very significant impacts on, what I'd refer to here as, adherence behaviours, or how compliant young people are with their medication, how well they do what their parents or health professionals would like them to do in relationship to following their treatment regimen. And this isn't because young people are silly, but rather, that young people in adolescence, it is normative that they are wishing to fit in and feel the same as their healthy peers. And that young people are far less likely to engage in behaviours such as taking medication at school, for example. If it renders them different to their healthy peers. So in this sense we can see in adolescence that young people are far more motivated by, if you like, short term social goals, things that matter in relationship to their social engagement with their peers in comparison to what perhaps adults may be more likely to be motivated by in the context of chronic dis, disease, which might be longer term health risks or complications of what might happen if young people, if, if adults don't take their medication. And for many young people, as, sad as it might be to their parents and to the health professionals, they are much more likely to learn by doing than to be learning from the experiences that others have gained by doing. And so for many young people, they actually have to experience the consequences of being poorly adherent, and the impacts of that on their health, before perhaps they are able to think about changing their behaviours as time goes on. And then finally, the notion of adolescent development as a time of onset of many health related behaviours has a very different significance for certain groups of young people with particular conditions. So for example, experimenting with substance use can be considered in many communities as being a normative aspect of adolescents. But this can have a very different or more significant, set of consequences if you like for young people with say, diabetes or epilepsy. So if we were to think about alcohol we know that in young people with diabetes, alcohol can greatly disturb the usual diabetic control. And in young people with epilepsy alcohol reduces the seizure threshold. Similarly we know that sleeplessness commonly experienced with young people who are out late or, or up studying or partying you know is a problem if you like, in terms of potentially missing school or having to sleep in for healthy young people but again, but again, but again, if we take the example of young people with epilepsy, sleeplessness of itself can reduce the seizure threshold and make it, more likely that young people will have, poor seizure control. I appreciate that this is a fairly complicated space that these last two slides are in. But I've just really tried to highlight some of these examples as a way of giving you a flavour of what you might want to think about in terms of the complexity of how young people growing up with chronic illness, of whatever type, in all off its different definitions and guises might experience adolescence itself, and the greater challenges that this group of young people in particular can face as they move into young adulthood.
