Differential diagnosis and comorbidity of ADHD and anxiety in adults

ObjectivesThe aim of this study was to examine symptom profiles of people diagnosed with attention-deficit/hyperactivity disorder (ADHD) and/or anxiety (ANX) in order to determine the validity of widely used ADHD and ANX rating scales for differential diagnostic use and to develop modified measures that take symptom overlap into account. DesignA cross-sectional design was used to assess differences in rating scale scores between clinical (n=52) and control (n=74) samples as well as differences among subgroups of the clinical sample (22 ADHD; 16 ADHD+ANX; 14 ANX). MethodParticipants completed an online questionnaire where they responded to the Conners Adult ADHD Rating Scale (CAARS; Conners, Erhardt, & Sparrow, ) and State Trait Anxiety Inventory scales (STAI; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, ). ResultsResults showed that the CAARS and STAI had limited sensitivity and specificity and may lack in ability to differentially diagnose ADHD and/or ANX. Cluster analysis was used to guide the proposal of modifications for the two scales, which were to use inattentive items only for the CAARS and to exclude state ANX-present items on the STAI for use in differential diagnosis. Further parametric analysis supported these proposed modifications. ConclusionsClinicians should be made aware of the limitations of the CAARS and STAI scales in terms of specificity, when used to inform differential diagnosis of ADHD and ANX. Further analysis on the psychometric properties of these modified scales is needed in order to confirm that they are valid and reliable scales.