The landscape for children's mental health services has changed dramatically due to the confluence of several factors. The emergence of managed care has influenced access to as well as the scope of primary care practice. Evidence-based medicine is steadily emerging and driving practice guideline development. In the rapidly changing and increasingly cost-conscious health services environment, care of children with mental health needs is shifting from mental health specialists to primary care providers. To meet these new needs, the Children's Mental Health Alliance Project was established as an interdisciplinary effort to review best practices in primary care in children's mental health; address under-recognition of mental health problems in youth; and clarify professional responsibilities across systems of care. This monograph summarizes their discussions, findings, and recommendations. Chapter 1 contains information on mental health problems in youth and the changing role of health providers. Chapter 2 concerns mental health screening. Chapter 3 discusses diagnosis of mental health disorders. Chapter 4 reviews efficacy and effectiveness. Chapter 5 reviews managed care and children's mental health. Chapter 6 discusses a systems approach. Chapter 7 presents recommendations from points of view of several participants in the field, and chapter 8 discusses issues for the future. (Contains 270 references.) (JDM)