Introduction

The leading causes of morbidity and mortality worldwide have been transformed dramatically over the past century. In the United States, since the early 1900s, there has been an unprecedented decline in the major infectious diseases of childhood, such as diptheria, scarlet fever, tuberculosis, and small pox. Simultaneously, there has been an increase in the prevalence of chronic diseases and disabilities, such as asthma, mental retardation, cerebral palsy, epilepsy, and childhood cancers. More recently there has been increasing concern for psychiatric, behavioral, and social disorders of childhood and a call for new methods to study and reduce these “new” psychosocial morbidities of childhood and adolescence (Buka & Lipsitt, 1994; Haggerty, Roughmann, & Pless, 1975).

This shifting profile of health concerns is not limited to either children or to the United States. Christopher Murray and Alan Lopez (1996) have conducted a comprehensive summary of the leading causes of mortality and disability, in 1990 and projected to 2020. To conduct this assessment, the Global Burden of Disease report calculated a single measure of the total “burden” that could be attributed to a particular disease or disorder, factoring in both the number of years lost (through premature death) and, for nonfatal diseases, the resulting losses in the quality of life. The resulting “Disability-Adjusted Life Year” (DALY) expresses years of life lost to premature death and years lived with a disability of specified severity and duration; one DALY represents one lost year of healthy life.