Three brief papers review the literature and report on a study concerning the concept of functional impairment in light of regulations requiring both a psychiatric diagnosis and functional impairment for access to mental health care by children and adolescents with emotional disturbances. The first, very brief summary is: "The Origin, Meaning and Use of Adaptive Functioning in Defining Mental Health Problems" (Sara M. Horwitz and others), which traces the history of the concept of adaptive functioning. The second summary is: "Service Needs and Use for Serious Emotional Disturbance: A Community Study" (E. Jane Costello). This study examined the prevalence of serious emotional disturbance (SED) in a large rural area and found that SED criteria identify about one child in 10, of which only one in three is currently receiving any services. The third summary is: "The Validity of Serious Emotional Disturbance as a Marker for Need for Services" (Adrian Angold). It finds that while the requirement of both psychiatric diagnosis and functional impairment does identify children with high levels of need for service, many children with marked functional impairment but less severe psychopathology will be excluded from services. (DB)