Prevalence of mental disorders in children living in Alberta, Canada, as determined from physician billing data

Background: The prevalence of mental disorders is often assessed using surv ey techniques. Although providing good estimates of prevalence, these techn iques are time-consuming and expensive. Objective: To estimate the prevalence of mental disorders among children ag ed 0 to 17 years living in Alberta, Canada, using health care administrativ e data. Design: This was a cross-sectional study. International Classification of D iseases, Ninth Revision, Clinical Modification chapter 5 diagnostic codes f rom physician billing data were used. Codes were grouped into 10 categories . Prevalence rates for each category were calculated, stratified by age, se x, and premium subsidy status (a proxy for socioeconomic status). The age p attern, times of greatest risk, and the effect of sex on type and prevalenc e of mental disorder were estimated. Setting: All fee-for-service health care venues in Alberta between April 1, 1995, and March 31, 1996, providing services to children registered with t he Alberta Health Care Insurance Commission on March 31, 1996. Results: Prevalence of mental disorders varied by disorder category, age, s ex, and premium subsidy status. For boys, maximum prevalence of 9.5% occurr ed at age 10 years; for girls, maximum prevalence of 12.0% occurred at age 17 years. Mental disorders were most common in young boys and adolescent gi rls and among children receiving welfare. Distinct patterns of disorder wer e evident and comorbidity was common. Conclusions: Administrative data can be used to estimate the prevalence of mental disorders in a pediatric population. The estimates made are lower th an those obtained by using surveys of similar populations, perhaps indicati ng the difference between treated and untreated prevalence. Strengths of th is study are that the estimates reflect the entire population, are more eas ily and obtained at less cost, and are useful for the planning of mental he alth services.