tinctions within the prevention category are given below.

Universal mental health prevention interventions are defined as efforts that are beneficial to a whole population or group. They are targeted to the general public or a whole population group that has not been designated or identified as being at risk for the disorder being prevented. The goal at this level is the reduction of the occurrence of new cases of the disorder.

Selective mental health prevention interventions are defined as those efforts that target individuals or a subgroup of the population whose risk of developing the mental health disorder is significantly higher than average. The risk may be immediate or lifelong. Biological, psychological, or social risk factors associated with or related to the specific mental health disorder are used to identify the individual or group level risk.

Indicated prevention interventions are defined as those efforts that target high-risk individuals who are identified as having minimal but detectable signs or symptoms that predict the mental disorder or biological markers indicating predisposition to the disorder. For example, individuals who have some symptoms of major depressive disorder but do not yet meet criteria for the disorder would fall into this group. Although this definition includes early intervention, it excludes individuals whose signs and symptoms meet diagnostic criteria for the disorder. In the Institute of Medicine (1994) definitions, interventions with individuals who meet diagnostic criteria would be considered treatment.

A further clarification of potentially confusing terms used within the prevention field was presented in the 1999 Surgeon General report on mental health (U.S. Department of Health and Human Services, 1999). In this report, first (initial) onset was defined as the initial point in time when an individual's mental health problems meet the full criteria for a diagnosis of a mental disorder. Risk factors were defined as those variables that, if present, make it more likely that a given individual, compared to someone selected at random from the general population, will develop a disorder. Although risk factors precede the first onset of a disorder, they may change in response to development or environmental stressors. Protective factors include factors that improve an individual's response to an environmental hazard and result in an adaptive outcome. These protective factors can be found within the individual or within the family or community. They do not necessarily lead to normal development in the absence of risk factors, but they may make an appreciable difference in the influence exerted by risk factors. We have adopted these clarifications offered in the Surgeon General's (1999) report here.

It is also important to distinguish between the risk of onset and the risk of relapse of a disorder. This is important because the risks for onset, or protection from onset, of a disorder are likely to be somewhat different from the risks involved in relapse, or protection from relapse, of a previously diagnosed condition. In this book, the prevention of relapse is included in chapters on treatment, whereas the prevention of onset of a disorder is discussed in chapters on prevention.

Each of the chapters on disorders in this book identifies treatments and prevention programs that have been found to work. What has become increasingly clear is that the development of such efficacious treatment is only a first step toward improving public health. It is also essential to take into account the settings in which the interventions occur. Currently in the United States, there are significant challenges to providing quality care for youth and their families within the mental health and substance abuse treatment systems that serve these populations. The severity of these challenges are highlighted in two chapters on service delivery systems for adolescents, one by Myers and McLellan regarding the substance abuse service delivery system in the United States, and one by Hoagwood on the mental health service delivery system. Both of these chapters document systemic barriers to implementing evidence-based treatments in our existing service delivery system. One of the primary barriers, reviewed in greater detail in Chapters 28 and 29, is service fragmentation—that is, the fact that treatment of children and adolescents is performed by at least six separate systems: specialty mental health, primary health care, child welfare, education, juvenile justice, and substance abuse. Other barriers include poor access and use of services among minorities, lack of sustained family involvement, and fiscal dis incentives under managed care. Thus, a research agenda for the future would not be complete without an understanding of and improvement in the relevant service delivery systems.

Schools have long been recognized as an important context for adolescent mental health development and service delivery. In fact, schools have been described as the de facto mental health service delivery system for children and adolescents, with between 70% and 80% of those that receive any form of mental health service obtaining such services from within the school setting (Burns et al., 1995). Higher prevalence rates of mental disorders and higher rates of comorbidity have been found among children and adolescents receiving services within the special education services of school than in specialty mental health clinics or in substance abuse clinics (Garland et al., 2001).

More than any other setting, schools provide access to adolescents for assessment and intervention. Student functioning, at least in terms of cognitive functioning needed for successful academic achievement, is tracked regularly, and behavior is assessed by multiple observers (teachers). At the first sign of problems, interventions could be initiated, rather than waiting until serious disorders develop and the adolescent is brought to a psychiatrist. Preventive interventions designed to target large populations of adolescents are particularly well suited for the school setting.

Unfortunately, as described in Chapter 31 on adolescent mental health and schools, the current state of mental health services in school is poor. There is wide variability across states and between urban and rural locations in the availability of mental health services in schools, with only about half of high schools having on-site mental health services (Brener, Martindale, & Weist, 2001; Slade, 2003). Increasing the availability and quality of school-based services for the assessment, treatment, and prevention of adolescent mental health problems is therefore a central component of any plan for improving the lives of adolescents.

A particular component of the service delivery system, primary care medical practice, merits special attention in regard to adolescent mental health. In a typical year, over 70% of young people visit a primary care physician (Wells, Kataoka, & Asarnow, 2001). Primary care physicians typically serve as the gateway to obtaining specialist care, including mental health services. However, primary care physicians are typically poorly trained in psychiatry and psychology. Results of a national survey of primary care residency programs revealed that the average program devotes about 100 hours over the course of 3 years of residency to psychiatry training, with little or none of this specifically in child and adolescent psychiatry (Chin, Guillermo, Prakken, & Eisendrath, 2000). Compounding the problem is the fact that primary care physicians have enormous time constraints, especially since the advent of managed care and health maintenance organizations. These time constraints make it difficult for primary care physicians to adequately diagnose mental health problems. A recent study of over 20,000 youths visiting a primary care physician revealed that such physicians identified mood or anxiety syndromes at a rate substantially lower than that found in epidemiological studies (Wren, Scholle, Heo, & Comer, 2003). Inaccurate or missed diagnoses will lead to inadequate treatment.

Chapter 30 addresses in more detail the issues of identification and treatment of adolescent mental health problems in primary care settings. A unique aspect of this chapter is the presentation of a new study, commissioned by the Annenberg Adolescent Mental Health Initiative, which evaluates the practices of primary care physicians who treat large numbers of adolescents in the United States. This study found that physicians are concerned about the mental health of their adolescent patients and regard mental health as an important responsibility. In addition, the vast majority of primary care providers believe in the efficacy of treatment for mental disorders. However, primary care providers report low confidence in their ability to diagnose mental health problems, and only half employ any screening technique at all to detect mental health problems in their adolescent patients. These results suggest that enhancement of the recognition of mental disorders and referral practices in primary care represents a significant opportunity to increase appropriate treatment of adolescent mental health disorders.