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Evidence-Based Interventions in Low- and Middle-Income Countries: The Tigress Awakens

      The articles included in this supplement investigate the neurobiology and development of adolescent health and disease, primarily focusing on what transpires during adolescence and how a young person subsequently responds to the full range of environmental demands placed on him or her [
      • Spear L.P.
      Adolescent neurodevelopment.
      ,
      • Wang G.
      • Walker S.O.
      • Hong X.
      • et al.
      Epigenetics and early life origins of chronic noncommunicable diseases.
      ,
      • Potenza M.N.
      Biological contributions to addictions in adolescents and adults: Prevention, treatment, and policy implications.
      ]. I would like to draw attention to the fact that we are dealing in issues with multiple determinants. Clearly, at the level of the individual, there is an interplay of beliefs, behaviors, and biology, which determines the balance between health and disease. At the level of the family and the community, there are perceptions, which are cultural; there are priorities, which are socioeconomic; and there are pathways of access to health promoting and supporting services and facilities. At the national and global levels, there is development in terms of stage and speed, as well as issues of equity related to the areas of education, income, social status, and gender. All of these factors impact on adolescents in contemporary society. So in looking at these issues, we must focus both on the individual as well as the larger social contexts.
      These articles focus in part on the neuroscience of the developing and differentiating human brain, particularly during the critical stage of adolescence [
      • Spear L.P.
      Adolescent neurodevelopment.
      ]. Further, these articles investigated the development of health and disease spanning across many periods, beginning with prenatal influences, moving to childhood, adolescence, and adulthood. Ultimately, the common message that emerges is that we need to adopt a life course approach to understanding adolescence. Focus as we may on the individual, we cannot forget that influences extend from the prenatal period through later adulthood [
      • Wang G.
      • Walker S.O.
      • Hong X.
      • et al.
      Epigenetics and early life origins of chronic noncommunicable diseases.
      ,
      • Potenza M.N.
      Biological contributions to addictions in adolescents and adults: Prevention, treatment, and policy implications.
      ].
      In these remarks, I will not attempt to summarize what has been presented; instead, I will offer my personal perspective as a meeting participant. Before I do so, however, let me offer a bit of background about myself. I have a great respect for evolutionary biology, and although it cannot explain everything in human science, I believe it provides unique insights into new areas of the biology of behavior. So too, I have a longstanding interest in developmental origins, partly because of my own collaborative work with David Barker, but also because it is not difficult to track the developmental origins of several health disorders, including tobacco exposure in early life and adult cardiovascular risk [
      • Barker D.J.
      In utero programming of chronic disease.
      ]. Similarly, over time, I have become convinced of neuroplasticity, which occurs even in adults, but certainly is best seen in early childhood and adolescence.
      With this in mind, I picked up a copy of National Geographic not long ago with the title, “The New Science of the Teenage Brain” [
      • Dobbs D.
      Beautiful Brains National Geographic.
      ]. The cover presents a figure of a teenager with a blurb that reads, “We are not as crazy as you think.” The article is brilliantly written, summarizing some of the current science, but it is this statement that I will defend as I begin my commentary on what I learned from the supplement articles. First, I would like to pose the question: are we talking about an immature brain or are we talking about a developing brain? From the work presented here, I think it is clear that adolescence is a stage in development and that the degree of neurobiological immaturity seen during this age is really a stage in the continued movement toward full maturity. Now, is adolescent behavior characterized by unpredictability or adaptability? As discussed here, this age period is defined by the ability to learn and to adapt—to not only apply new information, but also to shed what is not considered useful, in a remarkable display of flexibility. Therefore, what might be seen as unpredictability should be re-envisioned as a mechanism for adaptability. In terms of neurobiology, I would argue it is a developing brain rather than an immature brain, but above all, it is a learning brain.
      Whereas childhood is a stage of rapid neurodevelopment, adolescence is a stage of continued development with rapid differentiation, as evidenced by synaptic pruning processes, myelination, and back-to-front cortical development in which the prefrontal and frontal centers are actually developing later, resulting in a relative lack of cognitive control over subcortical structures. Furthermore, with this stage in development comes increased vulnerability, as highlighted in the phenomenon of hot cognition, which makes an adolescent more prone to emotional disorders and risk behaviors. But we must ask ourselves: why are these things occurring in the adolescent brain? Evolutionarily, the interplay of these forces provides a strong platform for new learning. As such, adolescence is an opportunity for enterprise, which warrants the risk taking associated with it. Reward is highly prized, even when risks do not seem to offer sure success. There is agility and ability to think, sift, shift, store, or shed new information. The adolescent brain keeps what is useful and discards what is not, all with the aim of helping the adolescent adapt to a changing world [
      • Spear L.P.
      Adolescent neurodevelopment.
      ,
      • Giedd J.N.
      The digital revolution and adolescent brain evolution.
      ].
      In many ways, one can think of an adolescent as analogous to an entrepreneur, or an innovator in Silicon Valley. You will see the same type of person in both cases: someone who takes risks, who prizes a huge early reward, and values that reward over the risks they face. In both cases, you see individuals with a remarkable ability to innovate as they grow. Contrast this, however, with a larger company, which has already grown and acquired stability, like an adult, but lost some of their previous mobility and flexibility. Think of IBM. With this in mind, I urge you to think of the adolescent brain as an evolutionary success story. It would be disappointing if it were otherwise.
      Although adults experience neuroplasticity as well, it is not to the same extent as in adolescents, who have a far greater capacity for absorption, assimilation, and adaptation. However, on the flip side, the hyper-reactivity of the adolescent brain can lead to vulnerability as well as risk behaviors. This is where we need to look at appropriate interventions. We need ensure that adolescents grow up in caring and supportive environments at home and in school so the triggers of hyper-reactivity are reduced, eliminated, or appropriately modified to reduce their risk of poor mental health outcomes or likelihood of engaging in risk behaviors. Given what we have learned from epigenetics—that the environment influences gene expression—we need to better understand how we can provide safe, supportive, and stimulating environments for the adolescent to explore and to grow without running into high risks [
      • Wang G.
      • Walker S.O.
      • Hong X.
      • et al.
      Epigenetics and early life origins of chronic noncommunicable diseases.
      ]. Indeed, this is the real challenge we face: integrating the new science into our existing policies and programs. Simply put, we need to make their environment safer.
      How do we actually do that? Obviously, we cannot restrict exploration, but we can ensure that adolescents face fewer hazards. Regulation of areas like tobacco and other addictive substances as well as food comes into play here [
      • Potenza M.N.
      Biological contributions to addictions in adolescents and adults: Prevention, treatment, and policy implications.
      ]. To control potential ill effects, we must regulate harmful practices through policies. Whether you are talking in terms of obesity or disorders like tobacco addiction, we find conditioned environments in which the market is playing a major role. Clearly, there is a need for regulation to make the environment less hazardous for the adventurous teenager. In addition to regulation, there is recognition of the need for scaffolding, given the various stages of development the adolescent brain traverses as it enters adulthood. For many behaviors, thresholds must be assessed in an age-appropriate manner, so protective measures can be taken through the scaffolding of certain interventions. A good example of this is the age at which alcohol can be sold or consumed. These issues need to be explored much further in the new brain science, not by handcuffing the adolescent, but ensuring a safer society.
      This is the responsibility that we bear. Just as the tigress allows her cubs to explore new surroundings as she keeps a watchful eye for predators, we must keep a watchful eye for industries preying on our youth, trying to invade their developing minds with marketable products. This is society's responsibility that we must reflect through our policies.
      Focusing specifically on low- and middle-income countries, we must synthesize what we have learned here and translate it to action. These articles clearly reflect a universal transference of basic biological knowledge, but they also carry with them an understanding about the kind of environments that are safe, supportive, and stimulating for adolescents. We have an opportunity at this point in time in the developmental trajectory of low- and middle-income countries to shape the environment through appropriate policies. So, the question for lower- and middle-income countries is how do we shape our society to provide these safe environments for adolescents while unleashing their evolutionary advantage into positive pathways for personal and societal advancement? The challenge is not merely for the health professional, but for those dealing with larger developmental issues, and therefore, the message of this particular supplement should be disseminated not only to professionals but also to policy makers, so that this understanding percolates into multiple policy and programmatic pathways.

      References

        • Spear L.P.
        Adolescent neurodevelopment.
        J Adolesc Health. 2013; 52: S7-S13https://doi.org/10.1016/j.jadohealth.2012.05.006
        • Wang G.
        • Walker S.O.
        • Hong X.
        • et al.
        Epigenetics and early life origins of chronic noncommunicable diseases.
        J Adolesc Health. 2013; 52: S14-S21https://doi.org/10.1016/j.jadohealth.2012.04.019
        • Potenza M.N.
        Biological contributions to addictions in adolescents and adults: Prevention, treatment, and policy implications.
        J Adolesc Health. 2013; 52: S22-S32https://doi.org/10.1016/j.jadohealth.2012.05.007
        • Barker D.J.
        In utero programming of chronic disease.
        Clin Sci. 1998; 95: 115-128
        • Dobbs D.
        Beautiful Brains.
        October, 2011
        • Giedd J.N.
        The digital revolution and adolescent brain evolution.
        J Adolesc Health. 2012; 51: 101-105https://doi.org/10.1016/j.jadohealth.2012.06.002