What is a psychometric test for ADHD



Summary:
Attention deficit / hyperactivity disorder (ADHD) is one of the most common mental disorders worldwide, beginning in childhood and adolescence, and often persisting into adulthood. The behaviors and experiences that arise from the core symptoms of inattention, hyperactivity and impulsiveness cause significant suffering in those affected, their families and their school and professional environment. Furthermore, the likelihood of developing comorbid mental disorders in people affected by ADHD is significantly increased, which additionally intensifies the suffering of those affected and the environment. In this context, the massive burden on health systems from ADHD becomes clear. A reliable diagnosis of the disorder in childhood is due to the overlap of the core symptoms of ADHD with central symptoms of other mental disorders (e.g. difficulty concentrating in depression), especially with regard to the still limited ability of introspection of younger children and the high reactivity of children and adolescents to disorders of the familial structures (in the sense of the index patient of systemic therapy), extremely demanding. With increasing age, with previously undiscovered ADHD, there is also the risk of developing a comorbid mental illness that may mask the underlying disorder. Diagnostic instruments must therefore, on the one hand, have a high degree of sensitivity for recording the symptoms and, on the other hand, a high degree of specificity in contrast to problematic behaviors and experiences, which can be better explained by other psychological disorders or problematic living conditions. In the context of cross-border research, it is also becoming clear that there are cultural differences in the assessment of the quality and intensity of ADHD core symptoms, i.e. which behavior is experienced as "problematic" by the social environment. For example, families with a migrant background living in Germany more often report ADHD symptoms in their children, which in turn are diagnosed less frequently (Huss et al., 2008). In this context, it must be checked whether a psychometric test method for diagnosing ADHD proves to be sufficiently valid and reliable for the largest possible population, or whether it may have to be adapted accordingly to subgroups (e.g. according to gender or cultural background). Self-assessments and external assessments of behavior and experiences with the help of questionnaires are among the most frequently used methods for recording ADHD symptoms, both in childhood and adulthood, which is why the first article (Schmidt, Reh, Hirsch, Rief, & Christiansen, 2013) dedicates this work to the possible influences of cultural variation on the reliability of the Conners-3 scales (Conners, 2008), a widespread questionnaire for recording ADHD in childhood. For this purpose, a group of children with a Turkish migration background living in Germany, as well as their parents and teachers, were examined. The evaluation of the data showed no relevant influence of acculturation in the assessment of the children's symptoms, regardless of whether the assessment was made by the parents or the teacher. In addition, the confirmatory factor analysis confirmed the factor structure of the original American version. Overall, the Conners-3 scales seem to be resistant to potential distortions in the context of cultural variation, which speaks for a suitability for the assessment of ADHD symptoms, regardless of the cultural background of the children. The retrospective diagnosis of ADHD in adulthood, a developmental disorder that begins in childhood, is made more difficult by the overlapping of the core symptoms with those of various other psychiatric disorders, for example concentration / attention problems in depression or impulsiveness, e.g. in substance-related and behavioral addictions or borderlines Personality disorder. The second article (Schmidt, Müller-Reh, Müller, Meyer, Rumpf & Christiansen) deals with the problem of the differential diagnosis of ADHD in adulthood. For this purpose, the short version of the Conners Adult ADHD Rating Scales (CAARS-S) was presented to both a group of ADHD-affected adults and test subjects who were affected by other disorders associated with impulse control deficiency. The results of the statistical evaluation indicate that the CAARS-S is generally well suited to adequately differentiate between these disorders. This applies in particular to the ADHD index subscale, the use of which alone showed an allocation accuracy of at least 82.5%. The guideline-based diagnosis of ADHD recommends the use of neuropsychological methods in addition to the use of questionnaires. These offer the advantage of a greatly increased objectivity compared to questionnaires and clinical interviews when recording the core ADHD symptoms. So far, however, these methods lack a sufficiently high specificity to differentiate between ADHD and other clinical disorders. The Quantified Behavior Test (Qb-Test; Ulberstad, 2012) is, in contrast to conventional neuropsychological methods, which are mostly limited to the detection of attention deficits and behavioral impulsivity, with the help of an infrared camera is able to monitor the subject's movements during the ongoing testing and thus to record motor abnormalities. The factor structure and psychometric properties of the Qb test are the subject of the third article (Reh, Schmidt, Lam, Schimmelmann, Hebebrand, Rief & Christiansen, 2013). Exploratory factor analysis, conducted with a large sample, identified a three-factor structure that is consistent with core ADHD symptoms. This is a first step towards improving the existing objective neuropsychological procedures with the help of the Qb test. Overall, the available study results speak for the following statements: 1.) the Conners-3 scales are resistant to distortions due to cultural variability and are therefore suitable for use in international studies on ADHD; 2.) the Conners Adult ADHD Rating Scales, in particular the ADHD index subscale, differentiate sufficiently well between ADHD in adulthood and other mental disorders associated with impulse control disorders; 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 with this method. The results of the work thus contribute to improving the diagnosis of ADHD in children and adults.

Summary:
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 of 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 analyzes 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 of capturing 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.