During the past year, we have devoted substantial efforts to investigate a wide range of mental health topics focusing on anxiety, mood, sleep and substance use disorders and psychotropic medication use in adolescents. Several active NCS-A work groups have continued to work with experts in the field from both intramural and extramural collaborators. We have identified the magnitude of mood disorders and the subtypes thereof defined by strict DSM-IV criteria, as well as the spectrum of mood disorders and subtypes. The most relevant findings involve the first presentation of mania in adolescence, whereas the traditional belief is that the onset of bipolar disorder occurs in the late 20s and 30s. Moreover, we found that rates of major depression are not significantly different among those with manic episodes compared to those of youth with other disorders such as anxiety disorders, behavior disorders or eating disorders. This suggests that mania is uncoupled from depression as it emerges in adolescence. As opposed to major depression, there was an approximately equal sex ratio of mania in adolescents. We also found that the structure of major depressive disorder is highly similar in adolescents and adults, but somewhat more complex in adults. Both studies show strong evidence for the significance of the atypical subtype, characterized by fatigue, increased appetite and sleep, and mood reactivity, particularly among adolescents. We further showed that the associations between cardiovascular disease and mood disorders were different across sexes, highlighting the importance of evaluating of sex differences in the biological underpinnings of these associations. Because of their strong overlap with depression both cross-sectionally and across the life course, we have also investigated the manifestations of anxiety disorders in adolescents. One of our most consistent findings is the markedly greater risk for pathology observed among youth who display multiple fears and/or forms of anxiety relative to those whose fear or anxiety remains circumscribed. Results also indicated that comorbidity across the anxiety disorders was relatively low, suggesting some utility of current diagnostic nosology for adolescents. Likewise, we investigated the prevalence and characteristics of social phobia, as well as the merit of DSM-5 proposed subtypes of this condition. We found that youth who endorsed a majority of social fears, defined as generalized social phobia, displayed higher levels of clinical severity, disability, and persistence than did youth with non-generalized forms of the disorder. The presence of specific phobia as a possible early indication of risk for other anxiety and psychiatric disorders was a particularly important finding that should be pursued in further research. In order to address the recent public criticism that the concept of social phobia was developed by psychiatrists working with pharmaceutical companies to medicalize shyness, we also demonstrated the validity of the diagnosis of social phobia and associated distress and impairment. This type of work fulfills the important role of epidemiology in public policy as well as its etiologic and benchmarking missions. Aside from our earlier findings (Merikangas KR, 2010; Merikangas et al, 2011) regarding the gaps in mental health service use in U.S. youth, subsequent papers have found that adolescent suicidality often is untreated in the U.S., which calls for increased outreach efforts to improve treatment access to youths with suicidal ideation and attempts. In investigations of psychotropic medication use in U.S. adolescents, we have reported 14.2% youth with any DSM-IV mental disorder have been treated with a psychotropic medication in the past 12 months. Strong associations emerged between specific disorders and classes of medications with evidence for efficacy. Our findings alleviate recent concerns over widespread over-medication and misuse of psychotropic medications in U.S. youth. In fact, our data highlight the need for greater recognition and appropriate treatment of youth with mental health disorders. In addition to our primary research topics in depression, bipolar, anxiety and mental health services, we have studied other psychiatric disorders that remain to be major public health concerns. These topics include alcohol and illicit drug use disorder, smoking, eating disorder, and childhood neglect. Our findings from eating disorder (anorexia, bulimia, and eating disorder not otherwise specified) research have important implications for subtype classifications and help to raise the public awareness of the impact of eating disorder demonstrated by its high comorbidity, role impairment, suicidality and unmet treatment. The Strengths and Difficulties Questionnaire (SDQ) is a brief psychiatric assessment scale to screen emotional and behavior problems in children and adolescents. Our investigation supports the original hypothesized five-factor structure of the SDQ (including emotional, conduct, hyperactivity-inattention, peer relationship, and prosocial behavior) and the findings indicate that the measurement invariant across sex, age, race/ethnicity and socioeconomic subgroups is evident in the U.S. adolescents. The reliability and construct validity of the SDQ and its strong associations with psychiatric disorders were also demonstrated. Public Health Impact: Aside from providing the first prevalence data on a wide range of psychiatric disorders in a nationally representative sample of U.S. adolescents, we believe that these analyses provide beneficial information to inform future research and treatment interventions. As mental health treatment research is moving into the translation of lab-based findings to treatment interventions, service level data provides us with an avenue to put our previous translational research into context and further enhance subsequent interventions. While the development of interventions is important, the ultimate success of intervention is predicated on the way this intervention is integrated into the existing medical system. Service utilization studies conducted within this group provide some insight into the populations and service sectors that could benefit from targeted interventions. Future Plans: We are currently preparing several other manuscripts for submission on a range of topics using NCS-A data, including: 1) Race/Ethnicity, immigration generation, and prevalence of mental disorders and service use; 2) Associations between neighborhood disadvantage and adolescent mental health; 3) The prevalence and correlates of major depression; 4) Prevalence, demographic and clinical correlates of Disruptive Mood Dysregulation Disorder (DMDD); 5) Comorbidity use pattern among substance abusers; 6) Prevalence, correlates and treatment patterns of Attention Deficit and Hyperactivity Disorder (ADHD) by sex and age groups; 7) Prevalence of insomnia symptoms and their mental and physical comorbidity; 8) Associations of social jetlag with mental disorder and suicidality; 9)The prevalence of migraine; and 10) The Strengths and Difficulties Questionnaire and its relationship with mental disorders and service use, in the U.S. adolescents.