Introduction

Adolescence is a critical developmental period biologically, psychologically, and socially. It is also a time of life during which many of the most serious mental disorders emerge—about one quarter of youth will experience a mental illness over the course of a year (Merikangas, Nakamura, & Kessler, 2009). This high rate underscores the critical need to understand the origins of mental disorders and to develop effective treatment and prevention interventions. As did the first edition, this second edition of Treating and Preventing Adolescent Mental Health Disorders aims to provide, in a single volume, a comprehensive review of current knowledge of serious mental health problems affecting adolescents, as well as efforts to enhance positive youth development. We again focus on six specific problem areas—mood disorders, anxiety disorders, substance abuse, eating disorders, suicide, and schizophrenia—as these typically first emerge during adolescence and, among many individuals, continue into adulthood. In the 10-plus years since the publication of the first edition, several developments have altered how these disorders are characterized and understood. The final section of the book describes emerging information on gambling and excessive Internet use, phenomena that have been termed “behavioral addictions,” and provides updated reviews of policy areas and broad recommendations for change that have the potential to improve adolescent mental health on a wide scale.

The sections focused on specific disorders review the major impact of the publication of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 on the description and conceptualization of these disorders. Among a number of important changes, DSM-5 eliminated the opening section of DSM-IV, Disorders Usually First Diagnosed in Infancy, Childhood, or Adolescence, in recognition of the fact that most psychiatric illnesses begin early in life and frequently continue into adulthood. The disorders in that section were distributed to thematically relevant sections in DSM-5. For example, the Feeding and Eating Disorders of Infancy or Early Childhood of DSM-IV (i.e., Pica, Rumination Disorder, and Feeding Disorder of Infancy or Early Childhood) were combined with the Eating Disorder section of DSM-IV to make up Feeding and Eating Disorders in DSM-5. Similarly, Separation Anxiety Disorder and Selective Mutism were moved into the section on Anxiety Disorders. In contrast, Posttraumatic Stress Disorder (PTSD) was relocated to a new section, Trauma- and Stress-Related Disorders, and Obsessive-Compulsive Disorder (OCD) to another new section, Obsessive-Compulsive and Related Disorders. One of the potentially most important changes in DSM-5 relevant to youth was the addition of a newly described disorder, Disruptive Mood Dysregulation Disorder, to the Depressive Disorders section of DSM-5, in hopes of providing clarity about presentations in some ways resembling Bipolar Disorder. In the DSM-5 section on Substance-Related and Addictive Disorders, the distinction between substance abuse and substance dependence was eliminated because of strong evidence that the relevant phenomena are more usefully viewed as occurring on a continuum. These and other changes to the diagnostic nomenclature are reviewed in this edition.

The years since the first edition have witnessed dramatic growth in investigators’ ability to safely and noninvasively observe brain structure and function in awake adolescents and adults, using magnetic resonance imaging (MRI), functional MRI, magnetic resonance spectroscopy, and electrophysiology. Emerging findings from these techniques are highlighted in this edition. For example, neuroimaging studies of young people with mood disorders have documented alterations in areas of the brain known to be involved in emotional regulation. Studies of youth with anxiety disorders have begun to explore changes in activity in areas that process information related to potential threats in the environment. Given the profound and clinically impairing neurocognitive deficits characteristic of schizophrenia, substantial effort has been devoted to assessing brain activity during the performance of cognitive tasks, such as those assessing attention and working memory, and to understanding how such changes evolve during adolescence among individuals at high risk.

At least arguably, our fundamental understanding of pathophysiological mechanisms and of disturbances in neural circuitry is clearest for substance use disorders. Research in this area has benefited from the availability of useful animal models and from extensive research in both animals and humans on the brain reward mechanisms, especially those involving mesolimbic dopamine. Recent work, examining both psychological and biological characteristics, aims at elucidating the impact of substance use on the developing brain and understanding why some individuals are more vulnerable; notably, although many adolescents experiment with drugs, relatively few develop substance use disorders.

Other new information relevant to investigators, clinicians, and policymakers has emerged. Epidemiological studies published in the past decade convincingly document that mood disturbances—which were once thought simply not to impact children and adolescents—affect a substantial minority, and that evidence of vulnerability may be observed before puberty. Recent studies continue to document a substantial frequency among adolescents of syndromes resembling adult bipolar disorder, but the nature and characteristics of bipolar disorder, as it appears during adolescence, remain subjects of some controversy and considerable debate. Recent treatment research has buttressed prior evidence regarding the efficacy of selective serotonin reuptake inhibitors (SSRIs) and of psychotherapy, especially cognitive-behavioral therapy and interpersonal therapy, for mood disturbances. There has been increasing focus on more complicated questions such as when and how they should be combined and on identifying what factors predict response to which treatments. Similarly, for many of the anxiety disorders, rigorous randomized trials have documented the benefits of specific forms of psychotherapy and of SSRIs, benefits that, at the time of the first edition, had been assumed to occur but had not been documented. Strong evidence has been developed since the first edition demonstrating that the active involvement of the family can be a critical therapeutic element in the treatment of adolescents with eating disorders and also for adolescents with substance abuse.

The identification and treatment of substance use disorders among adolescents remain high priorities, given that most affected adults began to abuse drugs as youths. Important epidemiological shifts are occurring in the United States. Likely related to the increasing legalization of marijuana, and to decreases in use of both alcohol and cigarettes, marijuana use among youth is now more prevalent than cigarette smoking. An increased number of emergencies associated with marijuana use and a decline in concerns about the risks of marijuana emphasize a need for better education and early intervention.

There is growing evidence that preventive interventions are of use. Universal prevention, aiming to benefit an entire population and reduce or even eliminate the initial development of clinical symptoms, is the ultimate goal. However, the resources required to develop and test such programs are daunting, and, from a theoretical perspective, it is not clear that a universal approach is best suited to the prevention of disorders that, while all too common, affect a minority of adolescents. Therefore, many prevention efforts are selective or indicated, focusing on high-risk youth and/or individuals who have already begun to develop symptoms. Growing evidence suggests that such targeted strategies, particularly those based on cognitive and familial interventions, have promise for the prevention of mood, eating, and anxiety disorders. In addition, there is intense and growing interest in the identification of individuals with prodromal psychosis, and the development of psychotherapeutic and pharmacological interventions to prevent progression to schizophrenia or, for those who have experienced a psychotic episode, recurrence.

Suicide among youth has increased markedly in the past 50 years and is the third leading cause of death among adolescents. The origins of suicidal behavior are multifactorial and include the presence of psychiatric disorders; recent evidence has also documented links to bullying and harassment by peers. The past decade has witnessed increased involvement of schools and school personnel in prevention efforts as well as the development of programs to identify previously unidentified youth at risk. However, many challenges persist, such as the expense of such programs and relatively poor rates of follow-through with treatment recommendations once individuals at high risk have been identified.

A novel and important element of the first edition was the inclusion of a chapter on positive youth development. As described in this edition, this approach has been increasingly studied and implemented in the past decade. While the problem-focused chapters review prevention efforts aimed at specific disorders, the chapter on positive youth development notes that targeting a single problem may miss an opportunity for a more integrated and more broadly effective approach. Evidence acquired since the first edition documents growing support for the utility of this approach, and its potential value in enhancing both physical and psychological health and educational achievement. However, clear challenges remain, for example in successful implementation in economically disadvantaged communities.

New to this edition are chapters on gambling disorder and on Internet addiction. These reflect an emerging interest in “behavioral addictions,” patterns of behavior that bear strong similarities to substance use disorders (e.g., persistent and excessive time committed to the behaviors, leading to interference with other activities; reluctance to disclose the level of involvement to others, including parents). It has been suggested that such behavioral addictions engage and distort the central reward-processing networks in a similar fashion to abused substances. We do not know precisely how to understand such phenomena and how they fit into the range of behaviors that individuals may find rewarding and to which they may devote substantial time and money (e.g., sex, exercise, shopping, work). Reflecting such uncertainties and the amount of peer-reviewed research, Gambling Disorder was officially recognized in DSM-IV (as Pathological Gambling) and was moved to the section retitled Substance-Related and Addictive Disorders in DSM-5, but Internet Gaming Disorder is included only in the DSM-5 section on Conditions for Further Study.

As did the first edition, this volume focuses not only on “what do we know?” but, importantly, also on “how do we implement change?” A thoroughly updated chapter on policy and practice highlights the impact of rapid changes that are under way in the delivery of healthcare in the United States. Major efforts are occurring at the state level to ensure that the mental health care of children and adolescents uses established evidence-based practices. At the federal level, groundbreaking legislation, including the Affordable Care Act, is producing profound changes in the infrastructure and financing of mental health care. The Affordable Care Act, combined with the passage of the Mental Health Parity and Addiction Equity Act, has the potential to have a major impact on the availability of treatment services for youth with mental disorders. In addition, standalone mental health centers are being replaced by facilities providing both medical and behavioral treatment. Research funding, for example from the recently established Patient-Centered Outcomes Research Institute, is increasingly focused on issues surrounding dissemination. These major shifts in healthcare policy and delivery have potentially profound implications regarding the mental health care of adolescents. As this volume goes to press in 2017, the implications of the recent national U.S. elections regarding these policies and developments are unclear but worrisome.

Finally, we note that there have been a number of changes to the list of contributors to this volume. Many of the contributors were re-enlisted, including all of the Annenberg Commission Chairs who provided leadership for the first edition. However, recent developments in the field, the inclusion of new topics, and the need for additional expertise led to some alterations in the contributors. We hope that the extensive efforts and hard work of all who contributed to the first and/or to the second edition will provide a foundation for advancing our understanding of, and enhance our ability to treat and to prevent, adolescent mental health disorders.