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 in epidemiological data. However, validation against clinical diagnostic assessments in a population-based sample has been lacking, limiting the implications for clinical practice, clinical research and public health decisions. METHODS: Study participants were recruited from the longitudinal Child and Adolescent Twin Study in Sweden (CATSS) inviting parents to all twins in Sweden. We investigated the psychometric properties of the A-TAC in 263 children, where one or both twins screened positive for neuropsychiatric problems, as well as control pairs, where both twins were screen negative. Study participants underwent thorough clinical examination within one year of the A-TAC interview. The psychometric properties of the A-TAC were then investigated. 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 (AUC ranging from 0.806 to 0.958), with exception for developmental coordination disorder (AUC = 0.616). 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. Although, A-TAC can be informative on neurodevelopmental problems in both clinical and population-based samples, it cannot replace a clinical neurodevelopmental investigation or be used to delimit individual access to specialized care.