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

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). 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 ( = 57,986) and 5 years ( = 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. 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]). The findings underline the importance of taking early parent-reported symptoms seriously. Both rating scales were useful for predicting ADHD.