The inter-relationship between depression, medication use and cognitive decline in older persons has potentially important clinical and public health implications, yet research findings on the nature of this relationship remain inconclusive. This thesis presents a systematic investigation into this topic in a sample of 281 medical inpatients aged 65 and over, who were followed for up to 12 months after admission. / In the first three chapters, the concept, population burden and measurement of depression and cognitive function in the elderly population are described. The relevant literature is reviewed, and the rationale and approaches of this thesis are presented. / In the fourth chapter (1st manuscript), the short-term temporal relationship between depression and cognitive functioning was explored using an interviewer-rated depression severity scale. Based on competing mixed effects models under alternative temporal assumptions, the severity of depression symptoms appeared to have a concurrent rather than prospective relationship with cognitive functioning. / In the fifth chapter (2nd manuscript), diagnostic criteria were used to define depression. After adjusting for covariates, both major and minor depression were significantly predictive of subsequent cognitive decline, and the strength of the association appeared to increase with the duration of "exposure". / In the sixth chapter (3rd manuscript), using a provincial prescription database, the effects of medication exposure on cognitive function were evaluated. Antidepressant use was not associated with cognitive decline in general, but interacted with depression diagnoses. In exploratory analyses, antidepressant use appeared to be associated with improved cognitive function over time in the minor depression group, independent of comorbid diseases, current depression symptoms and concomitant medications. Both major and minor depression were independently predictive of subsequent cognitive decline, especially in those not prescribed antidepressants. / In summary, this thesis demonstrates that, in this sample of older medical inpatients, both major and minor depression are independent risk factors for 12-month cognitive decline. The potentially beneficial effects of antidepressants for patients with minor depression should be investigated.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.103161 |
| Date | January 2006 |
| Creators | Han, Ling, 1955- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Epidemiology and Biostatistics.) |
| Rights | © Ling Han, 2006 |
| Relation | alephsysno: 002584931, proquestno: AAINR32356, Theses scanned by UMI/ProQuest. |
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