What single reports from children and parents aggregate to attention deficit-hyperactivity disorder and oppositional defiant disorder diagnoses in epidemiological studies.

Objective: To analyze information on attention deficit-hyperactivity disorder (ADHD)-oppositional defiant disorder (ODD) and its consequences, provided separately or in combination by children and their parents in a longitudinal prospective study of 9-15 year-old children from the general population.

Method: Cross-sectional and longitudinal epidemiological indexes were compared for single and multiple reports. We evaluated which informant is required for the identification of each DSM-IV criterion. Logistic regressions determined which features were related with the reporting of the "absence" of symptoms.

Results: Both informants were required in order to obtain complete psychopathological profiles. Single reports provide infra-estimated prevalences (between 8.8 and 22.9% of ADHD and between 1.7 and 7.6% of ODD), risks (around 3% for ADHD and 2% for ODD) and comorbidities. Psychological and functional measures analyzed in the study were relatively similar for cases presenting ADHD/ODD diagnosis, regardless of the diagnostic algorithm (based on single or combined reports); however, these clinical profiles were different to those obtained for non-diagnosed children. The main predictors of not reporting the presence of psychopathology were: large families (OR between 2 and 2.5), children that are conflictive at school (OR ranging between 1.3 and 4.3) or those with poor mental health (OR between 1.1 and 1.6).

Conclusions: These results may provide guidance for obtaining accurate diagnostic information, properly identifying children with mental health needs and planning the required preventive and corrective measures.