Syndromes versus symptoms : towards validation of a dimensional approach of depression and anxiety

Wardenaar, K.J. (2012)

Doctoral Thesis

There is a growing awareness that research of the etiology of depressive and anxiety disorders has been hampered by their strictly categorical definition in the Diagnostic and Statistical Manual (DSM). The DSM uses a syndrome approach, which __ although beneficial for standardization - has inherent problems that make it suboptimal for research: high rates of (artificial) comorbidity, diagnostic heterogeneity and the unrealistic assumption of discontinuity between ill and healthy. A dimensional approach that focusses on the relative severity of continuous symptom domains could be more optimal but measurement and the added value of such dimensions has been debated. Therefore, this dissertation was aimed to investigate (1) the internal validity and possibility to measure dimensions and (2) their added value in etiological and clinical research. The results showed that measurement of dimensions can be optimized using self-report questionnaires. In addition, dimensions were shown to have added value in etiological and clinical research. Because of their specific and continuous nature, dimensions could be used to uncover symptom-specific and/or non-linear association. Together, the results suggest that dimensions of depression and anxiety have internal and external validity and have the potential to improve the psychiatric research.

• Validity
• Dimensions
• Dimensional psychopathology
• Depression
• Anxiety

• All authors: Wardenaar, K.J.
• Supervisor: Zitman, F.G.; Penninx, B.W.J.H.
• Co-supervisor: Giltay, E.J.; Veen, T. van
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden University Medical Center (LUMC), Leiden University
• Date: 2012-10-04
• Sponsorship: The infrastructure for the NESDA study (www.nesda.nl) is gratefully acknowledged. The NESDA infrastructure is funded through the Geestkracht program of the Netherlands Organisation for Health Research and Development (Zon-Mw, grant number 10-000-1002) and is supported by participating universities and mental health care organizations (Vrije Universiteit University Medical Center, GGZ inGeest, Arkin, Leiden University Medical Center, GGZ Rivierduinen, University Medical Center Groningen, Lentis, GGZ Friesland, GGZ Drenthe, Scientific Institute for Quality of Healthcare (IQ healthcare), Netherlands Institute for Health Services Research (NIVEL) and Netherlands Institute of Mental Health and Addiction (Trimbos Institute). GGZ Rivierduinen is gratefully acknowledged for making the Routine Outcome Monitoring database available for analysis. The infrastructure for the NESDA study (www.nesda.nl) is gratefully acknowledged. The NESDA infrastructure is funded through the Geestkracht program of the Netherlands Organisation for Health Research and Development (Zon-Mw, grant number 10-000-1002) and is supported by participating universities and mental health care organizations (Vrije Universiteit University Medical Center, GGZ inGeest, Arkin, Leiden University Medical Center, GGZ Rivierduinen, University Medical Center Groningen, Lentis, GGZ Friesland, GGZ Drenthe, Scientific Institute for Quality of Healthcare (IQ healthcare), Netherlands Institute for Health Services Research (NIVEL) and Netherlands Institute of Mental Health and Addiction (Trimbos Institute). GGZ Rivierduinen is gratefully acknowledged for making the Routine Outcome Monitoring database available for analysis. Faculty of Medicine / Leiden University Medical Center (LUMC), Leiden University