A-TAC - The Autism–Tics, ADHD and other Comorbidities inventory: studies in reliability and validity

Abstract: Introduction: Reliable, valid, and easy-to-administer instruments to identify possible “caseness” and to provide proxies for clinical diagnoses are needed in epidemiological research on child and adolescent mental health. The Autism–Tics, ADHD and other Comorbidities (A-TAC) inventory was developed to be used as a comprehensive interview to evaluate neurodevelopmental problems (NDPs), e.g. autism spectrum disorders (ASDs) and attention deficit hyperactivity disorder (ADHD), and coexisting disorders in childhood and adolescence. Aims & Methods: The overall aim of this study was to present basic reliability and validity data on the A-TAC and to investigate its screening application in epidemiological and clinical studies. Specific aims were to determine: (1) the A-TAC’s test–retest reliability; (2) the psychometric properties and establish optimal cut-off values for NDP modules of the A-TAC in order to differentiate between clinically diagnosed children and others; (3) the A-TAC’s convergent validity with the Child Behavior Checklist (CBCL); (4) its diagnostic predictive screening properties in a population-based cohort; and (5) to establish basic prevalence figures for NDPs and provide an overview of the comorbidity, distribution and intercorrelation of these problems with the A-TAC. Results: There were good test–retest intraclass correlations for both ASDs and ADHD (intraclass correlation coefficient (ICC) 0.84 for both). Areas under receiver operating characteristic curves (AUCs) for interview scores were excellent predictors of clinical diagnoses, around 0.95 for most disorders. Screening cut-off scores with sensitivities >0.90 could be established for most conditions. The A-TAC has overall convergent validity with the CBCL, and works well as a predictive assessment tool in the general population, with AUCs from 0.77 (ADHD) to 0.91 (ASDs). Finally, NDPs are dimensionally distributed in the general population, with a total of 16% being screen-positive for one or several of the targeted disorders (1.3% for ASDs and 5.6% for ADHD). Conclusions: The A-TAC inventory is a reasonably reliable and valid tool even when administered by lay persons over the telephone, yielding both sensitive screening measures and proxies for clinical diagnoses. The A-TAC has a particularly good ability to assess features and problems in the ASDs and their most common comorbid conditions.