Table of Contents:
Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common psychological disorders with onset in childhood and adolescence that often persists into adulthood. Its core symptoms inattention, hyperactivity and impulsivity cause significant suffering among those affected, as well as for their families and school or professional environment. Furthermore, the likelihood of developing comorbid mental disorders is significantly increased. Healthcare systems of affected countries are massively strained. A reliable diagnosis of the disorder in childhood is a challenging task due to overlap of symptoms of ADHD with central symptoms of other mental disorders (e. g. difficulties concentrating in depression). Other problems are the limited introspective abilities of young children and the high reactivity of children and adolescents concerning dysfunctional family structures. With increasing age an undiagnosed ADHD also increases the risk of developing a comorbid mental illness that might cover the underlying disorder. Diagnostic instruments must therefore have a high degree of sensitivity for the detection of symptoms specific for ADHD, while simultaneously displaying a high degree of specificity towards problematic behavior that might more accurately be associated with other mental disorders or contexts. Transnational research showed that there are some serious cultural differences in assessing the quality and intensity of ADHD core symptoms, in terms of what kind of behavior is experienced as "problematic" by the social environment. Therefore, it is a necessity to verify whether a psychometric test for the diagnosis of ADHD is sufficiently valid and reliable when administered to the widest possible population, or whether it has to be tailored to specific subgroups (e. g. gender or varying cultural backgrounds). Self- and external assessment questionnaires are among the most commonly used method for detecting ADHD symptoms, both in children and adults, which is why the first paper (Schmidt, Reh, Hirsch, Rief & Christiansen, 2013) of this work is dedicated to test the possible influences of cultural variation on the reliability of the Conners-3 scales (Conners, 2008), a popular questionnaire for the assessment of ADHD in childhood. To achieve this, we examined a group of children with Turkish migration background living in Germany, as well as their parents and teachers. The analysis of the data showed no relevant influence of acculturation when assessing the symptoms of children, regardless whether the assessment was done by the children, their parents or their teachers. In addition, the confirmatory factor analysis confirmed the factor structure of the original US version. Overall, the Conners-3 scales seem to be resistant to distortion through cultural variation, which recommends their suitability when assessing ADHD symptoms, regardless of cultural background.
Retrospective diagnosis of adult ADHD, a developmental disorder with onset in childhood, is complicated as its core symptoms overlap with those of several other psychiatric disorders, such as depression (concentration/attention problems) or behavioral and substance-related addictions as well as Borderline Personality Disorder (impulsivity). The second paper (Schmidt, Müller-Reh, Müller, Meyer, Rumpf & Christiansen) thus deals with the problems of differential diagnosis of adult ADHD. To this end, the short version of the Conners Adult ADHD Rating Scales (CAARS-S; Conners, 2010) was presented to both a group of adults affected by ADHD, as well as subjects who were affected by other disorders associated with a lack of impulse control. The results of the statistical analyses indicate a good overall suitability of the CAARS-S to adequately differentiate between these clinical pictures. This applies in particular for the subscale ADHD Index, which achieved an accuracy rating of 82.5%.
A guideline-based diagnosis of ADHD not solely relies on questionnaires but uses the assessment of neuropsychological processes as well. In contrast to questionnaires and clinical interviews these offer the advantage of substantially increased objectivity when assessing core ADHD symptoms, although this method currently lacks sufficiently high specificity for differentiation of ADHD and other clinical disorders. The Quantified Behavior Test (Qb-Test; Ulberstad, 2012) - in contrast to conventional neuropsychological methods that are mostly limited to the detection of attention deficit and behavioral impulsivity - uses an infrared camera capable to capture the movements of the subject during the testing, and thus is able to detect motor abnormalities. Factor structure and psychometric properties of the Qb-Test are subjects of the third paper (Reh, Schmidt, Lam, Schimmelmann, Hebebrand, Rief & Christiansen, 2013). An exploratory factor analysis conducted with a large sample identified a three-factor structure that matched the ADHD core symptoms. This is a first step towards improving the existing objective neuropsychological procedures using the Qb-Test. On the basis of the study results the following statements are made: 1.) the Conners-3 scales are resistant to distortion by cultural variability and thus suitable for use in international studies on ADHD; 2.) the Conners Adult ADHD Rating Scales, especially the subscale ADHD Index, differentiate adequately between adult ADHD and other problematic behaviors, associated with impulse control; and 3) the determined factor structure of the Qb-Test suggests that an improvement in the objective assessment of ADHD core symptoms can be achieved using this method. Altogether this work contributes to the improvement of current processes when assessing ADHD in children and adults.