Smoking remains a leading cause of disability and mortality worldwide. Despite declining rates of smoking in developed countries, smoking prevalence remains high, and there is evidence that it has plateaued in recent years. Individuals with a comorbid psychiatric diagnosis represent a disproportionate percentage of those who continue to smoke and are particularly at-risk given they smoke at higher rates and consume more cigarettes compared to those with no diagnosis. Moreover, these individuals are often excluded from clinical trials of smoking cessation, making it difficult to generalize results of previous intervention studies. In the general literature of smoking cessation, smoking cessation self-efficacy, or one’s confidence in their ability to abstain from smoking, is a consistent predictor of positive abstinence outcomes. The overall purpose of this dissertation was to investigate smoking cessation self-efficacy as a predictor of abstinence outcomes in a population of treatment-seeking smokers with and without a history of psychiatric illness. To accomplish this, articles 1 and 2 investigated the psychometric properties of a multi-item measure of cessation self-efficacy. This entailed comparing the measure to other indices of smoking, and conducting a confirmatory factor analysis to ensure factor invariance and equivalence of the measure regardless of psychiatric status. We found a moderate correlation between our multi-item scale to a single-item measure of confidence to quit, as well as support for both the original two-factor model as well as a three-factor model, which explained 79.3% of the variance. Our results also supported the measure as being factor invariant across psychiatric diagnoses. Next, articles 3 and 4 investigated how this measure of cessation self-efficacy predicted several smoking outcomes (10-, 22- and 52-weeks following target-quit date), and whether this relationship was mediated by concurrent smoking and other interpersonal-indices of smoking cessation (nicotine withdrawal, negative affect). In article 3, we found support for a bidirectional and reciprocal relationship between smoking cessation self-efficacy and smoking status. While changes in concurrent behavior (smoking or abstinent) did impact subsequent evaluations of self-efficacy, the inverse was also true. Moreover, both concurrent smoking and cessation self-efficacy predicted outcomes at week 10. Article 4 built on this framework and investigated this relationship at 22- and 52-weeks post-target quit-date. Our results highlight the robust association between cessation self-efficacy and abstinence. Higher cessation self-efficacy was positively associated with better abstinence outcomes, even after controlling for concurrent smoking, withdrawal, and negative affect. Further, there was evidence that cessation self-efficacy partially mediated the impact of withdrawal and negative affect. In our fully adjusted model (adjusting for demographic characteristics, baseline smoking levels, withdrawal and negative affect), cessation self-efficacy along among the interpersonal-determinants predicted abstinence outcomes (Odds ratio = 1.078, 95% confidence interval (1.068 - 1.089). This was true for those with either a current, past, or no lifetime psychiatric diagnosis, and despite the finding that individuals in the lifetime (current or past diagnosis) category experienced overall lower self-efficacy. Overall, our results support the value of cessation self-efficacy as an important indicator of abstinence outcomes, and particularly highlight its potential utility for at-risk populations of comorbid psychiatric smokers.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/39104 |
| Date | 26 April 2019 |
| Creators | Clyde, Matthew |
| Contributors | Tulloch, Heather Elizabeth |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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