Introduction: The association between smoking and depression has been well established, but the nature of the relationship has not been determined. A synthesis of longitudinal studies examining the onset of smoking and depression among adolescents demonstrated consistent evidence of both smoking predicting depression and depression predicting smoking in multiple populations; however, more work is needed to develop and test the mechanisms associated with the onset of the co-occurrence of smoking and depression. This thesis examines the role of a broad range of potential confounders on the relationship between smoking and depression, and investigates a potential mechanism of effect.
Method: Analyses were conducted using the Nicotine Dependence in Teens (NDIT) cohort which included 1293 students initially aged 12-13 years recruited from all grade seven classes in a convenience sample of ten secondary schools in Montreal, Canada surveyed twenty times over five years. Multiple regressions were performed to examine the temporal relationship of potential confounders on the relationship between smoking and depression and to empirically observe variables that could be intermediate on pathways between smoking and depression. A growth curve model was developed to test the effect of perceived self medication on changes in depression scores over time.
Results: A concept map of the smoking and depression relationship in the NDIT cohort was developed according to the results of proportional hazard and fixed effect regressions in which friend smoking, stress, and anxiety-associated variables were identified as intermediate variables. Perceived self-medication was associated with decelerated rates of change of depressive symptoms over times, suggesting that smoking may increase mean levels of stress and depressive symptoms, but may offer the perception of control.
Conclusion: In concert, this thesis suggests a model in which stress and the perceived control of psychobiological function using cigarettes lead to the development of increased depressive symptoms and increased cigarette use.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/24701 |
| Date | 05 August 2010 |
| Creators | Chaiton, Michael |
| Contributors | Cohen, Joanna |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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