Objective: Concerns have been raised over observed increases in the number of children who are given a diagnosis of a neurodevelopmental disorder. The goal of this study was to examine trends by age and calendar year in the diagnosis of two of these disorders, autism and attention-deficit hyperactivity disorder (ADHD), in the context of other psychiatric disorders in a sample of hospitalized children.
Methods: Data from the Healthcare Cost and Utilization Project (HCUP) were used for descriptive analyses of secular trends of diagnosed psychiatric disorders between 1989 and 2000. Changes over time in rates of diagnosis of autism, ADHD, affective disorders, and substance-related disorders were examined and compared.
Results: Substance-related disorders were the most common mental disorders recorded at hospital discharge and increased by 39 percent between 1989 and 2000. Affective disorder was the next most common diagnosis and increased by 138 percent. Although autism and ADHD were far less common, their diagnosis rates nearly quadrupled over the course of the study. Although rates of diagnosis of affective and substance-related disorders generally increased over the lifespan, diagnosis of autism and ADHD followed a very different pattern, with peaks in rates at ages seven and 12.
Conclusions: Increases in rates of diagnosis of etiologically unrelated mental disorders suggest that there have been changes in diagnostic practices over time, increases in community prevalence of these disorders, and increased likelihood of hospitalizations for different mental disorders.