published_or_final_version / Statistics and Actuarial Science / Master / Master of Philosophy

Research on risk factor for suicidal behaviors has been broadly conducted to enhance knowledge of suicide prevention. However, there are still challenges for risk factor research. Four major research gaps have been identified: (1) uncertain effectiveness of the population approach versus the high-risk approach for suicide prevention; (2) lack of a valid and convenient Chinese-version screening tool for the severity of suicidal ideation among adolescents; (3) demand for testing the prospective associations of risk factors with suicidal ideation using a longitudinal designed population-based sample; and (4) necessity of pathway analysis to explore and confirm how risk factors interact with each other and lead to suicidality. This thesis aims to address these gaps through a combination of five studies. Study 1 introduces an illness and death model to suicide prevention research. Elasticity and sensitivity analyses were performed. The findings revealed that the control of suicide incidence among the healthy population is the most effective prevention strategy whereas treatment of mental illness appears to be the least effective approach to suicide prevention. Study 2 validates the psychometric properties of the Chinese versions of Reynolds’s Suicidal Ideation Questionnaire (SIQ) and Suicidal Ideation Questionnaire Junior (SIQ-JR, a short version of the SIQ) in a sample of Hong Kong adolescents. A short, four-item version of the SIQ-JR has been suggested as an alternative to the SIQ and the SIQ-JR. Study 3 identifies the history of psychiatric treatment, depression, anxiety, hopelessness, unstable marital status, poor economic circumstance, and a recent death of a first-degree relative as significant risk factors for the incidence of suicidal ideation. The associations of change in risk factors with the development of suicidal ideation have been tested. There are gender and age differences in the patterns of such associations. Study 4 focuses on psychological factors associated with the first-ever incidence of suicidal ideation. Psychological factors have been detected generally to differ in their associations with the incidence and persistence of suicidality. The idea that depression partially mediates the effect of average life distress on the persistence of suicidal ideation has clinical value. Study 5 introduces and tests a stressor and illness model as a theoretical framework reference for future risk factor research. Risk factors are classified into stressor, illness, and pattern factors. Both the simple and complex models are tested. Evidence supported the proposed mediating role of mental disorders between negative life events and severity of suicidal ideation. A gender-specific pattern of associations between stressors, illness, and severity of suicidal ideation has also been detected. This thesis has made substantial theoretical, psychometric, and empirical contributions to the existing knowledge of suicide research. / published_or_final_version / Social Work and Social Administration / Doctoral / Doctor of Philosophy

In this dissertation the literature on suicidal behaviour is reviewed, with particular emphasis on professional conceptualizations and understanding as informed by the psychiatric and sociological paradigms. Basic postulates of the Ecosystemic paradigm, as it is informed by Maturana's second-order cybernetic approach was discussed. The effect of such an approach on therapy with suicidal individuals was pointed out. It became clear that perceived methodological problems experienced when researching suicidal behaviour from a Newtonian/realist paradigm can be side-stepped when viewed from an Ecosystemic paradigm. It was finally proposed that an ethic of participation, as informed by a second-order cybernetic approach, be adopted when viewing the suicide situation. In the process ethics was reconceptualized as an awareness of the therapist's participation in whatever is created, and not in finding the ''right" way when working with suicidal individuals. / Psychology / M.A. (Clinical Psychology)

My thesis aims at identifying both genetic and environmental causes of major depressive disorder (MDD), using a large case-control study: 6,000 Chinese women with recurrent MDD and 6,000 controls. One of the major challenges for conducting genetic research on MDD is disease heterogeneity. The first question addressed is how different MDD is from highly comorbid anxiety disorders. I examine how anxiety disorders predict clinical features of depression and the degree of heterogeneity in their predictive pattern. The second question addressed is whether clinically defined MDD is a single disorder, or whether it consists of multiple subtypes. Results are then compared with and interpreted in the context of Western studies. Furthermore, latent class analysis and factor analysis results are also used in association analysis to explore more genetically homogeneous subtypes. Genetic data were derived using a novel strategy, low pass whole genome sequence analysis. Using genotypes imputed from the sequence data, I show that a cluster of single nucleotide polymorphisms (SNPs) is significantly associated with a binary disease phenotype including only cases with = 4 episodes of MDD, suggesting that recurrence might be an indication of genetic predisposition. The third issue examined is the contribution of rare variants to disease susceptibility. Again using sparse sequence data, I identified exonic sequence variants and performed gene-based analysis by comparing the number of variants between cases and controls in every gene. Furthermore I performed gene enrichment test by combining P values of SNP association tests at different minor allele frequency ranges. Overall, I did not find convincing evidence that rare variants aggregately contribute to disease susceptibility. However, the gene-based analysis resulted in an unexpected finding: cases have an excess of variants in all thirteen-protein coding mitochondrial genes, which was due to copy number differences in the mitochondrial genome. Both human phenotypic data as well as mice experimental data show that the increase in the mitochondrial copy number in cases is due to chronic stress.

In this dissertation the literature on suicidal behaviour is reviewed, with particular emphasis on professional conceptualizations and understanding as informed by the psychiatric and sociological paradigms. Basic postulates of the Ecosystemic paradigm, as it is informed by Maturana's second-order cybernetic approach was discussed. The effect of such an approach on therapy with suicidal individuals was pointed out. It became clear that perceived methodological problems experienced when researching suicidal behaviour from a Newtonian/realist paradigm can be side-stepped when viewed from an Ecosystemic paradigm. It was finally proposed that an ethic of participation, as informed by a second-order cybernetic approach, be adopted when viewing the suicide situation. In the process ethics was reconceptualized as an awareness of the therapist's participation in whatever is created, and not in finding the ''right" way when working with suicidal individuals. / Psychology / M.A. (Clinical Psychology)

This thesis provides a fresh investigation of a collection of Roman imperial biographies conventionally known as the 'Historia Augusta'. The thesis supports the authenticity of the texts included in this corpus, in particular the claims they make about their dates, authorship, and scope, through philological, literary, prosopographical, and historical arguments. It shows that this corpus of texts, if the main conclusions are accepted, potentially improves our understanding of the tetrarchic-Constantinian era. It also explores the wider implications for the historiography of the fourth century; the transmission and formation of multi-author corpora in antiquity and the middle ages. It also suggests that the canon of Latin imperial biographies be widened. The thesis has two parts. Part I explores the actual state of the corpus, its textual transmission, and relation to other texts. It shows that the ancient and medieval paratexts presented the corpus as a collection of imperial biographies. The paratexts are compatible with the authorial statements in the main text. It then explores the corpus' medieval transmission, and the interest medieval scholars had in such texts. This part suggests that the corpus’s current state explains well the inconsistencies found in it. Finally, it shows that words and phrases, once thought peculiar to the corpus and the holy grail of the forgery argument, are intertextual links to earlier texts. Part II explores chronological statements and historical episodes relevant to the Diocletianic-Constantinan period. It establishes the actual dates of each author, and suggests that the confusion found in these biographies is similar to that of other contemporaries. The few apostrophes are shown to be authentic, and the historical and prosopographical passages are shown to represent, and improve our understanding of, the zeitgeist and history of the period. The final conclusion weaves the various arguments together, and emphasises the authenticity and significance of the corpus' texts. It suggests separating the composition of the texts from the disinterested formation of the corpus as a whole, as part of a new hypothesis and further lines of enquiry.