Universität zu Köln

Thöne, Ann-Kathrin ORCID: 0000-0003-2082-1757 (2024). Categorical and dimensional concepts of externalizing disorders in children. PhD thesis, Universität zu Köln.

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Abstract

One of the most difficult challenges faced by researchers and clinicians is how to best conceptualize the classification of mental disorders. Can we assume that there is a clear distinction in which an individual is either ‘normal’ (i.e., not meeting diagnostic criteria) or ‘abnormal’ (i.e., meeting diagnostic criteria)? And should we continue to endorse this black-and-white mindset, even though reality presents us with various shades of gray? Or should we not rather assume that the frequency and severity of psychological symptoms vary continuously across the full range of each dimension, without any distinct, meaningful binary threshold between 'having' or 'not having' a mental disorder? These questions have sparked an ongoing debate regarding whether it is more appropriate to conceptualize mental disorders using categorical or dimensional approaches– a debate that holds significant implications for scientific research and clinical practice. Building upon this debate, the main objective of this doctoral dissertation is to contribute to establishing a rigorous standard for diagnosing mental disorders in childhood and adolescence. Having developed the DISYPS-ILF, an extensive set of clinical parent interviews for diagnosing mental disorders, this dissertation provides a comprehensive psychometric evaluation of the Interview for Externalizing Disorders (ILF-EXTERNAL). The ILF-EXTERNAL covers diagnostic criteria for attention-deficit/hyperactivity disorder and disruptive behavior disorders. One major advantage of the ILF-EXTERNAL compared to existing clinical interviews is that it allows both a categorical assessment and a dimensional characterization, thereby integrating the strengths of both diagnostic approaches. Participant data (N = 474) for analyses of this dissertation were obtained from the ESCAschool (Evidence-based, Stepped Care of ADHD in school-aged children) multicenter trial. This doctoral dissertation is designed as a cumulative work and comprises three empirical studies. The first study (Thöne et al., 2020) assesses the psychometric properties of the ILF-EXTERNAL. Overall, the ILF-EXTERNAL displays sound psychometric properties in terms of validity and reliability. Furthermore, diagnostic agreement between clinicians is generally higher at the dimensional level compared to categorical diagnoses. The second study (Thöne et al., 2021) evaluates the factorial structure of the ILF-EXTERNAL and systematically tests the underlying latent dimensions of externalizing symptoms using confirmatory factor analyses and exploratory structural equation modeling. Specifically, results demonstrate that a novel bifactor S-1 factor model displays a statistically sound factor structure and allows for meaningful interpretation. Besides, results from measurement invariance analyses highlight meaningful cross-informant discrepancies, that is, different informants (i.e., clinicians, parents, teachers) provide unique perspectives how children’s behavior varies across settings, such as at school or at home. The third study (Thöne et al., 2023) zooms in on the symptom-level and enhances the understanding of how individual symptoms differentially relate to psychological distress and functional impairments. Overall, results from the multivariate regression analyses demonstrate significant variations in the associations between symptoms and global functional impairment. Furthermore, results from network analyses reveal a more nuanced yet multifaceted perspective on the associations between individual symptom-impairment relations compared to factor-analytic techniques. In conclusion, findings from this doctoral dissertation, especially the comparison of latent factor and network models, demonstrate that there is no simple or comprehensive solution to the categorical versus dimensional debate from an empirical perspective. Both categorical and dimensional approaches have their merits and combining both approaches may help to compensate for each other’s shortcomings. These findings, whilst intriguing, represent only the beginning of the journey and there is still a need to investigate categorical and dimensional concepts as well as recently proposed hybrid systems of psychopathology in greater detail. In the future, there needs to be further focus on the clinical utility of empirically identified dimensions, their clinical implications regarding the selection of appropriate treatments and adaptive interventions, and systematic research on patient outcomes when adopting dimensional instead of categorical measures of psychopathology.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Thöne, Ann-Kathrin ann-kathrin.thoene@uk-koeln.de orcid.org/0000-0003-2082-1757 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-731252
Date:	2024
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Psychiatrie und Psychotherapie > Psychiatrie und Psychotherapie des Kindes- und Jugendalters
Subjects:	Psychology Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Structured interview UNSPECIFIED Externalizing disorders UNSPECIFIED ADHD UNSPECIFIED Bifactor models UNSPECIFIED Network analysis UNSPECIFIED
Date of oral exam:	28 May 2024
Referee:	Name Academic Title Vogeley, Kai Prof. Dr. Dr. Albus, Christian Prof. Dr. Hanisch, Charlotte Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/73125