Is it possible to determine the level of functional impairment that distinguishes the patients with ADHD from those without ADHD?

Introduction Functional impairment in attention deficit hyperactivity disorder (ADHD) can occur in many areas such as in family, social activities, and problems related to school and may also persist during adulthood. The Weiss Functional Impairment Rating Scale-Parent Form (WFIRS-P) is designed to measure the functional impairment related to ADHD symptoms. The aim of this study was to determine the level of functional impairment that distinguishes the patients with ADHD who were diagnosed through semi-structured interviews from those without ADHD. Method This study consists of ADHD patients who were diagnosed through semi-structured interview aged 5-18 years (n = 250) and same age gender-matched healthy controls (n = 250). A receiver operating characteristic (ROC) curve was constructed by calculating the sensitivity and specificity of the scale cut-off values. Results An area under the curve (AUC) of 0.974 (95% CI 0.956-0.986) was found in this study. For WFIRS-P subdomains, AUC curves, which range from 0.76 to 0.95, were also having strong power for differentiation between groups. The optimal cut-off value for WFIRS-P using Youden's J Index is 0.32. There is no significant gender and age group differences in AUC for either the total or subdomain scores. Conclusion Our findings provide that Turkish version of WFIRS-P could be a reliable way of distinguishing the level of functional impairment in ADHD from controls.