Thorough clinical child psychiatric diagnostic evaluation and validation of the Autism- Tics, ADHD and other Comorbidities inventory (A-TAC) in a population- based sample of 9-year-olds 

Background The Autism- Tics, ADHD and other Comorbidities inventory (A-TAC) has been validated cross-sectionally, longitudinally, and validated against diagnoses in epidemiological data. However, validation against clinical diagnostic assessments in a population-based sample has been lacking. Methods We investigated the psychometric properties of the A-TAC in 263 children who underwent thorough clinical examination within one year of the A-TAC interview. We also mapped the extent of comorbidity of neurodevelopmental disorders. Results Using the A-TAC as screening for neurodevelopmental disorders we could discriminate two groups of children with clearly different occurrences of clinical diagnoses. The predictive screening properties of the A-TAC were good for most of the neurodevelopmental disorders, with exception for developmental coordination disorder. More than 40% of children fulfilling diagnostic criteria for a neurodevelopmental disorder, also fulfilled diagnostic criteria for at least one other neurodevelopmental disorder. Conclusion This study confirms the utility of the A-TAC interview as a screening tool for neuropsychiatric disorders in a non-clinical sample. It also supports the necessity to maintain a broad diagnostic approach in clinical child psychiatric investigations for meaningful understanding of the child’s problems.