Systematic review of self-report measures of depression, suitable for use with people with progressive neurological conditions; and, An examination of the relationship between psychological flexibility and loneliness in older adults

Portfolio Abstract Background: Ageing is associated both with a higher likelihood of developing a progressive neurological condition, such as dementia, or for a neurological condition such as MS to deteriorate. The impact of these on social relationships and on depression are likely, and yet reliable measurement in this area is not well developed. This thesis therefore sought to contribute to research and practice in this field by reviewing available measures of depression for people with neurological conditions, and assessing relationships between age, loneliness, interpersonal difficulties and psychological flexibility. Methods: A systematic review of studies assessing the validity and reliability of self-report measures of depression for use with people with progressive neurological conditions was carried out. The studies were quality assessed using COSMIN criteria. Findings of studies were pooled to allow overall recommendations about the use of the identified measures to be made. A cross-sectional study was carried out with older adults using standardised measures to identify the relationship between loneliness and psychological flexibility and the subsequent impact on anxiety, depression and quality of life. A step-by-step process was used to develop statistical models of these relationships. Conditional process analysis was used to identify mediating and moderating factors in these relationships. Results: The systematic review identified 14 studies assessing the validity and reliability of six different measures. The approaches used to assess the validity and reliability of measures varied, as did the quality of the evidence. It is suggested that the Geriatric Depression Scale may be the most appropriate self-report measure for use with people with progressive neurological conditions. Regression analysis showed that loneliness, interpersonal difficulties, attachment anxiety and psychological flexibility were significant predictors of anxiety, depression and quality of life. Using conditional process analysis, psychological flexibility significantly moderated the relationships between attachment anxiety and the outcome variables. Conclusion: Recommendations for how validation studies could be improved are made, in the hopes that this may allow those carrying out future reviews to be able to draw sound conclusions from a larger body of evidence. Psychological flexibility may play an important role in the mitigation of loneliness in older adults and may help protect against the development of mental health difficulties.