Continuity of psychiatric disorders between 6 and 11 years of age in the 2004 Pelotas Birth Cohort

OBJECTIVE: To investigate the incidence and homotypic and heterotypic continuity of psychiatric disorders between ages 6 and 11. METHODS: In 2004, all live births in the city of Pelotas, Brazil, were recorded (n=4,231). Psychiatric disorders were assessed by the Strengths and Difficulties Questionnaire (SDQ). SDQ subscale scores (emotional symptoms, conduct problems, hyperactivity/inattention, and peer relationship problems) were categorized as normal or abnormal. To examine associations between problems over time, odds ratios were computed using logistic regression. RESULTS: Any SDQ difficulty was observed in 350 children (10.4%, 95%CI 9.4-11.5) at age 6 and 476 (14.2%, 95%CI 13.0-15.4) at age 11, with a higher prevalence among boys at both ages. Between ages 6 and 11, there was a 50 and a 45% increase in the prevalence of emotional and hyperactivity/inattention symptoms, respectively. Among those who had any SDQ difficulty at age 6, that status persisted in 81% at age 11. We found homotypic continuity of emotional symptoms, conduct problems, hyperactivity/inattention, and peer relationship problems. CONCLUSIONS: Our results indicate an increasing incidence of psychiatric disorders in this age group, with rates of disorders and continuity patterns similar to those observed in other studies.