Prevalence and comorbidity of psychiatric disorders among 6-year-old children: 2004 Pelotas Birth Cohort - Petresco, Sandra; Anselmi, Luciana; Santos, Iná S.; Barros, Aluísio J. D.; Fleitlich-Bilyk, Bacy; Barros, Fernando C.; Matijasevich, Alicia (Social Psychiatry and Psychiatric Epidemiology, 2014)