In the previous lecture, I introduced the idea of risk and protective factors. Why these are particularly important in the context of adolescent development, and what the range of intervention strategies might be for promoting health in adolescents. In this lecture, I want to talk further about these approaches to using this understanding of risk and protective factors. Risk and protective factors inform the health actions that we take with young people. This slide illustrates the range of possible health interventions or health actions that we might consider with adolescents, or for that matter, with any other age group. These actions range from those that we might take to maintain health and prevent the onset of problems, to those that we might use for those with more established physical and mental health problems. As we move to the right, we are dealing with interventions that are mostly delivered through health service systems. So there are a group of adolescents with chronic or relapsing diseases, both medical and psychiatric, where the principal focus is on preventing relapse and managing disability. So the young person can not only maintain health, but also accomplish the other developmental tasks they're facing. Examples include young people with type 1 diabetes, asthma, or schizophrenia. Or it might be meeting the needs of an adolescent who has suffered a major physical injury. Or perhaps a child who has developed a major health-related disability early in life, such as an adolescent with cerebral palsy or intellectual disability. We generally estimate that at least one in five adolescents have that level of physical and mental health problems that presents a need for ongoing management of this kind. And Susan Sawyer is going to be talking more about this in a later lecture. More commonly, young people come into contact with health services without a chronic health problem. The focus is sometimes on early intervention, where the intent is to shorten the course of a potentially longer lasting health problem and minimize its impact on other aspects of development. And again, Susan will talk more about this in a later lecture. Prevention is where the focus is generally on risk and protective factors, and this can take many forms. Some aspects of prevention are very much to do with health service action. Examples include, the provision of contraception when needed, or providing vaccination such as that for the human papillomavirus, HPV, or perhaps the provision of bed nets for the prevention of malaria. Others are actions in sectors outside of health, and these may be in schools or local communities. Indicated prevention refers to the targeting of individuals with low levels of symptoms of a particular health problem. It's really an extension of early intervention approaches. There has been much interest in this approach for the prevention of mental health problems in adolescents, for example, in young people who are reporting low levels of anxiety or depressive symptoms. Selective prevention targets a group who are at high risk for developing a particular problem. So this might be, for example, the counseling of adolescents who have been bullied or victimized, or perhaps proactive intervention for groups at high risk of particular diseases, for example, young sex workers in a region where HIV is endemic. Universal interventions target the whole of a population. Examples of a universal intervention would include universal sex education, or provision of nutritional supplements, such as iron, to all girls in a population at risk, or that example of HPV vaccination. Lastly, health promotion refers to strategies that support healthy development and is very much about putting protective factors into the environments, social and physical, in which young people are growing up. The targets are commonly aspects of adolescent lifestyle that we know to be related to health and health risks, certain things like physical activity, diet, nutrition, and sun exposure. In this next slide, I want to discuss the process for preventive intervention in whatever the setting. The principles behind this process will apply whether the intervention is designed for a local village, or local neighborhood level, or for a district or state level. And it applies whether the intervention be around prevention of infectious diseases such as HIV, or problems such as early unwanted pregnancy, or the prevention of substance abuse. The first step in prevention, or in programming, is about defining the problem. So the question becomes, what are the particular health needs of adolescents in this setting? In some places, the biggest health problems will relate to HIV, or perhaps other aspects of sexual and reproductive health. In other places, the major health problems may relate to injury and violence, or mental health problems and substance abuse. This knowledge of what is important in a particular local context determines which risk and protective factors are likely to be the most useful targets for intervention. The next step will be to examine and understand the risk and protective factors that are most relevant in that local setting. These are likely to be the risk factors that are generally the most common in that setting, or the protective factors that are least common. As I will show in the next slide, many risk and protective factors predict multiple health and social problems. Homelessness or being out of school are examples of factors that influence many aspects of health. Others are more specific, for example, a knowledge of HIV transmission in settings where HIV is endemic, is protective. Or helmet use in settings where rates of road traffic injury are very high for young people riding on bikes. Or perhaps access to guns or other lethal weapons in settings where homicides are particularly high. Based on the profile of risk and protective factors, the community can then take actions that are targeted to the particular profile of risks and protective factors in that setting. Many of these interventions will be in those settings that we discussed in the previous lecture. They're going to be interventions with families, in school settings, community settings, or perhaps around the peer context. The last step is that of implementing and evaluating. Implementation will take place in different ways in different places, and depend on what the most appropriate locally available platform for delivery might be. As I discussed in an earlier lecture, secondary school retention rates are increasing in many parts of the world. In those settings, schools are likely to become a new and important platform for the delivery of many preventive health actions. This slide has presented this process in a stepped way. In reality, this is a circular process where the evaluation typically gives a new reading of the major health problems, which, if your intervention has been successful, will change over time. I mentioned that some factors that may be a target for intervention can affect multiple health problems in adolescents. This slide illustrates what some of those factors are. Community or local neighborhood factors are important in all settings that young people are growing up in. So community attitudes, community connection, the presence of risks such as guns, access to alcohol, tobacco or drugs, or stigma around sexual activity in unmarried adolescents, commonly have profound effects on the health of young people growing up in that setting. The most important influence in the lives of young people are their families. And what happens within families matters greatly for health. Parental values, family conflict, parental management style, and family affluence all have profound implications for health risk. We've talked about staying in school through the secondary years as one of the most effective interventions for promoting the health of adolescents. Where adolescents are in school, the quality of engagement with the school, with the teachers and peers, and with academic work is a further substantial, significant protective factor. Lastly, there are factors in the individual and the peer group that may heighten risks. Bullying, attitudes of friends to substance use are good examples of risk factors that are modifiable. At the top of this slide are a range of health and social problems in adolescents. So if we take a look at substance abuse, it should be clear that many of the risk and protective factors outlined in this table heighten the risks for substance abuse in adolescents. This means that actions to prevent substance abuse should ideally be taking into account many of these settings and many of these risk factors. In contrast, we understand much less about the risk factors for common mental health problems, depression and anxiety. Family factors such as the family history and family conflict we know to be important. So too are peer factors such as bullying, but the range of targets for preventive intervention here is somewhat less than it is for substance abuse. It should be clear that some factors increase the risk for multiple health problems, and family conflict is one such risk factor. Interventions that diminish family conflict, make families a better place for young people to grow up, are likely to have multiple benefits for adolescent health and social development.