Early Predictors of ADHD: Evidence from a Prospective Birth Cohort.

Objective:To identify preschool predictors of registered ADHD diagnoses and compare two ADHD rating scales, Child Behavior Checklist (CBCL) and Conners' Parent Rating Scale (CPRS-R:S).Method:The Norwegian Mother and Child Cohort study (MoBa) is a prospective population-based cohort study. The sample were singletons whose mothers responded to MoBa questionnaires at child age 3 years (n= 57,986) and 5 years (n= 32,377). ADHD diagnoses were obtained from the Norwegian Patient Register. Predictors were child gender, development and symptoms, and maternal ADHD symptoms. We used Cox proportional hazard regression analyses.Results:In all final models, ADHD symptoms at age 3 and 5 years predicted later ADHD: Age 3, CBCL: hazard ratio (HR) = 3.23 (CI [2.59, 4.02]); age 5, CBCL: HR = 10.30 (CI [7.44, 14.26]); and age 5 CPRS-R:S: HR = 5.92 (CI [4.95, 7.07]).Conclusion:The findings underline the importance of taking early parent-reported symptoms seriously. Both rating scales were useful for predicting ADHD.