The aims of this thesis were to gain more insight into the prevalence and associations with mortality of loneliness and social isolation, while trying to unravel the role of depression in this interplay. In addition, possible pathways in the associations between both loneliness and social isolation and mortality were investigated. A further goal was to identify certain groups of older adults who are especially vulnerable to loneliness and/or social isolation. Finally, the effects of loneliness and social relationships on the outcome of depression treatment were examined. Chapter 2 describes the meta-analysis that was performed to investigate the associations between loneliness and mortality and between social isolation and mortality in older adults, and the role of depression in these associations. Both loneliness and smaller social network size were associated with a small but significantly increased mortality risk in older adults. In comparison with studies that included younger people, loneliness and social network size appear to play a less significant role with respect to mortality. Chapter 3 describes the NESDO-study into the association between loneliness and the hypothalamic-pituitary-adrenal axis. The results show a lower cortisol output in the first hour after awakening in lonely older adults, irrespective of depression. In Chapter 4 the association between loneliness and cardiovascular disease in the NESDO population is investigated. The results show that only in women, loneliness is associated with cardiovascular disease. However, this association can be explained by the presence of depression. Therefore, it was concluded that no association was found between loneliness and cardiovascular disease. Chapter 5 describes a NESDO-study into the association between social network size and cortisol, as well as between both loneliness and social network size and mortality. In the first part of the study, no association between social network size and cortisol was demonstrated. In the second part of this study, no association with mortality was found for either loneliness or social network size. It could be that as people grow older the variety of factors that influence mortality risk increases, thus diminishing the effect of a single factor. Chapter 6 describes a NESDO-study investigating the association between ‘big five’ personality characteristics and both loneliness and social isolation. It appeared that the personality characteristics higher neuroticism and lower extraversion were associated with loneliness in women only, and lower agreeableness was associated with loneliness in both men and women. These associations were not influenced by the presence of depression. In non-depressed men and women only, there was an association between lower openness and loneliness. Chapter 7 tries to find answers to the questions: ‘What is the prevalence of loneliness in older psychiatric outpatients?’ and ‘What are the roles of respectively social isolation factors and depression?’ Here research is described that was done at the geriatric psychiatry-department of Arkin Mental Health Care. The results show that the prevalence of loneliness in older psychiatric patients is very high (80%). In women only, having social contacts in more network domains was associated with less loneliness. Furthermore, as in previous research (Lara et al. 2017) loneliness was not associated with DSM-IV-TR classifications, but was associated with severity of symptoms of depression. Chapter 8 deals with the question ‘What role does loneliness play in the treatment outcome of depression?’ It describes the results of a combined Netherlands Study of Depression and Anxiety (NESDA) and NESDO-study. The only significant predictor of non-remission was a negative experience of social support. In comparison, significant predictors of a reduction in depression severity were having a partner, and living in a household of three or more persons. In men only, loneliness was associated with a reduced decrease of depression severity.
|Qualification||Doctor of Philosophy|
|Award date||3 Feb 2022|
|Place of Publication||Ede|
|Publication status||Published - 3 Feb 2022|