Prevalence of psychiatric disorders in a Brazilian birth cohort of 11-year-olds

Objective To estimate the prevalence of psychiatric disorders in preadolescents aged 11-12 years from a birth cohort in a southern Brazilian city. Methods This is a cross-sectional investigation nested in a cohort study with a two-phase design: screening and diagnosis. In the screening phase, 4,452 preadolescents and their mothers were interviewed with the Strengths and Difficulties Questionnaire (SDQ). In the diagnostic phase, all preadolescents with a positive SDQ (n = 122) and their mothers answered the Development and Well-Being Assessment for Children and Adolescents (DAWBA). A sample randomly selected among the cohort participants with a negative SDQ served as a control group (158 subjects and their mothers) and was also assessed using the DAWBA. Results After adjustment for the performance of the screening instrument, 10.8% (95% CI 7.1-14.5) of the preadolescents showed at least one psychiatric disorder according to either the DSM-IV or the ICD-10. The most prevalent disorders were disruptive behavior (prevalence rates were 8.5% according to the DSM-IV and 7.1% according to the ICD-10) and anxiety disorders (prevalence rates were 6.0% according to the DSM-IV and 6.2% according to the ICD-10). Conclusion Both overall and individual prevalence rates of psychiatric disorders found in this study are in the same range of other international studies, although slightly higher than findings from developed countries. The results corroborate previous findings from other epidemiological studies in children and adolescents suggesting the universality of psychiatric disorders across cultures.