ADHD Rating Scale (ADHD-RS): Validation in Spanish in adult population according to the DSM-5

Abstract

Introduction

Attention deficit hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder, with an estimated prevalence in adulthood of 2.5–3.4%. The Attention Deficit/Hyperactivity Disorder Rating Scale (ADHD-RS) is an 18-item self-administered scale that assesses attention deficit and hyperactivity/impulsivity symptoms of ADHD in adults. This study aims to validate the ADHD-RS in Spanish according to the diagnostic criteria established by the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

Materials and methods

A sample of 441 adult patients (mean age 33.34 ± 11.37 years) was included, 396 subjects were diagnosed with ADHD (mean age 33.17 ± 11.18 years), and 45 were controls (mean age 35.40 ± 12.33 years). The clinical diagnosis of ADHD was established according to the DSM-5 criteria. The ADHD-RS was subsequently administered to all participants.

A logistic regression study evaluated the model in terms of sensitivity, specificity, positive predictive value, and negative predictive value. The Kaiser-Meyer-Olkin (KMO) measure was performed to assess the adequacy of the data set, and to determine whether factor analysis was applicable, Bartlett's sphericity test was performed.

Principal component analysis was used, using the Varimax orthogonal rotation method, which minimizes the number of variables with high loads on each factor, obtaining two factors and thus, simplifying their interpretation.

Results

The cut-off point that best discriminates the combined presentation of ADHD was 24 points, with a sensitivity of 94.78%, a specificity of 84.79%, a PPV (positive predictive value) of 93.74%, and an NPV (negative predictive value) of 78.33, with an area under the curve (AUC) of 0.85, and a kappa coefficient of 0.86.

Regarding inattentive ADHD, the cut-off point that best discriminates was 21 points, with a sensitivity of 92.56%, a specificity of 76.26%, a PPV of 92.01%, an NPV of 78.33%, an AUC of 0.90, and a kappa coefficient of 0.87.

Different cut-off values in the two subgroups suggests that a differentiated cut-off point for the inattentive and combined presentations may be an adequate assessment strategy for ADHD in adulthood.

Conclusions

The Spanish version of the ADHD-RS is a valid instrument to evaluate ADHD in adults according to the diagnostic criteria established by the DSM-5.

Differentiated cut-off points for the inattentive and combined presentations discriminate more accurately than a single cut-off point.