Objective: Using data from an epidemiological survey, the study compared existing definitions of severe mental illness and serious emotional disturbance among children and adolescents to demonstrate the range of prevalence rates resulting from application of different definitions to the same population.
Methods: Three definitions of severe mental illness and serious emotional disturbance were applied to data from the Methods for the Epidemiology of Child and Adolescent Mental Disorders survey, with a sample of 1,285, conducted in 1991-1992 by the National Institute of Mental Health. The resulting proportions of cases identified, demographic characteristics, service use, and perceived need for services were compared.
Results: From 3 to 23 percent of the sampled youth met criteria for severe mental illness or serious emotional disturbance. From 40 percent to as many as 78 percent of the defined youth used a mental health service in the year before the survey. School and ambulatory specialty settings were used most frequently. Generally, more than half of the parents of children with severe mental illness or serious emotional disturbance thought that their child needed services.
Conclusions: The prevalence and characteristics of severe mental illness and serious emotional disturbance among children are sensitive to the definition used and its operationalization. Care should be taken by policy makers and service planners to avoid either over- or underestimating the prevalence of impaired youth in need of intensive interventions.