Depression shows a large heterogeneity of symptoms between and within persons over time. However, most outcome studies have assessed depression as a single underlying latent construct, using the... Show moreDepression shows a large heterogeneity of symptoms between and within persons over time. However, most outcome studies have assessed depression as a single underlying latent construct, using the sum score on psychometric scales as a total indicator for depression severity. The present dissertation aimed to expand our knowledge of depression by researching its symptom-specific longitudinal characteristics, its predictive factors, and methods for predicting depression and anxiety while taking individual symptoms into account. We demonstrated that individual depressive symptoms are not synchronized over time within patients and in groups of patients. We found that individual symptoms of depression are associated to different risk factors, as preceding chronicity, neuroticism, and inflammation were related to individual symptoms with vastly different magnitudes. Taken these findings together we have demonstrated that depressive disorder can not be characterized as an unified syndrome. Addressing depression at the syndrome level may obscure insights into both patient and symptom-specific characteristics. Our findings strengthen the idea that employing a symptom-focused approach in both clinical care and research is of value. With this dissertation, we hope to have contributed to the development of alternative ways to define and study depression and its symptoms. Show less
The aim of this thesis was to clarify which aspects of depression and anxiety are related to an increased metabolic risk, and which factors contribute to these associations. Taken together, our... Show moreThe aim of this thesis was to clarify which aspects of depression and anxiety are related to an increased metabolic risk, and which factors contribute to these associations. Taken together, our findings indicate that people with more severe symptoms of depression and anxiety are at particular risk of progressive dyslipidemia and (abdominal) obesity. The higher rates of smoking and systemic inflammation among people with depression or anxiety partially accounted for their adverse metabolic profile. Dysregulations of the autonomic nervous system partly explained why users of tricyclic antidepressants displayed an increased risk of dyslipidemia and (abdominal) obesity as well, and also of hypertension. These important findings shed light on useful avenues for future research, and on preventive and therapeutic insights and directions. Show less
