published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

This thesis pertains to the uses of Functional Data Analysis and Machine Learning when analyzing high-dimensional structured datasets. The theme that motivates the first two chapters is the development of dimension-reduction methods in the context of functional data to advance the understanding of in-vivo measurements of neural-spike data. The last chapter addresses the analysis of survey data using machine learning techniques to identify novel risk factors for suicide in the general population. The first chapter of this thesis, "Adaptive Functional Principal Component Analysis," provides a novel method for adequately capturing modes of variation in data exhibiting sharp changes in smoothness. Our work integrates a novel scatterplot technique that adaptively smooths latent functions estimated in an FPCA framework. We are motivated to identify coordinated patterns of brain activity across multiple simultaneously-recorded neurons during motor behavior to understand the dynamics between the brain and dexterous movement. Our proposed method adequately captures the underlying biological mechanisms in our experiment, offering interpretable activation patterns when compared to standard approaches. The second chapter of our dissertation develops statistical procedures to compare the eigendecomposition from two samples of functional data. We first introduce appropriate tests for both independent and paired functions. We are motivated to test whether activation patterns in the motor cortex hold constant when a mouse performs a reaching movement repeatedly. We test all pairwise comparisons across trials and compare the distribution of the p-values against the distribution under the null. Our results suggest trial-to-trial variation in the latent activation patterns that can't be attributed to sampling noise. Our results can inform future methodology for deriving activation patterns from noisy neural spikes. The last chapter of this dissertation dives into applying Machine Learning Techniques to analyze survey data. We use the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) survey to identify novel risk factors for suicide attempts in the general population. Our analysis uses a Balanced Random Forest (BRF) approach and incorporates extreme class imbalance and survey architecture into the algorithm. We extend prior research focusing on high-risk clinical samples by identifying risk factors for suicide attempts in the general population. Our work identifies risk variables that can help guide clinical assessment and the development of suicide risk scales.

Wu Chi Hang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 41-49). / Abstracts in English and Chinese. / List of Figures --- p.i / List of Tables --- p.ii / Chapter Chapter 1: --- Introduction to the Study --- p.1 / Introduction --- p.1 / The Role of Family Problems --- p.3 / The Mediating Effect of Self-Perception --- p.5 / The Mediating Effect of Beliefs about the World --- p.7 / Combining Self-Perceptions and Social Beliefs as Mediators --- p.11 / Gender Difference in the Mediation Model Interactions --- p.11 / Chapter Chapter 2: --- Method --- p.13 / Sample and Procedures --- p.13 / Instruments --- p.13 / McMaster Family Assessment Device (FAD) --- p.13 / Perceived Stress Scale (PSS) --- p.14 / Depression-Cognition: Cognition Checklist ´ؤ Depression (CCL-D) --- p.14 / Rosenberg Self-Esteem Scale --- p.14 / The Social Axioms Survey --- p.14 / Suicidal Ideation Questionnaire (SIQ) --- p.15 / Analysis --- p.16 / Chapter Chapter 3: --- Results --- p.17 / Correlation among Variables --- p.17 / Exploratory Factor Analysis of FAD and Self-Perceptions --- p.18 / Mediation Analysis for Suicidal Ideation --- p.20 / Model Containing both Mediators --- p.24 / Testing Gender Differences in the Model --- p.28 / Chapter Chapter 4: --- Discussion --- p.31 / Family and Suicidal Ideation --- p.31 / Family as a System --- p.32 / The Role of Social Beliefs --- p.34 / A Gender-General Model for Suicidal Ideation --- p.37 / Implications and Further Research --- p.38 / References --- p.40 / Appendix --- p.49

Psychologists and other mental health professionals working in correctional institutions bear the considerable responsibility for identifying, diagnosing, and treating mentally disordered inmates. The importance of these responsibilities has been recognized in recent years because of the burgeoning population of inmates in general and the higher numbers of inmates with mental illness in particular. Research has demonstrated that the screens currently used in correctional settings to identify mentally disordered and suicidal inmates are either unvalidated or generally ineffective. This study investigates the validity of different mental health screens in a jail population. Inmates from the Grayson County Jail were administered three screens: the Referral Decision Scale (RDS), Personality Assessment Screener (PAS), and the Mental Disability/Suicide Intake Screen (MDSIS). Criterion measures were the Schedule for Affective Disorders and Schizophrenia (SADS) for Axis I disorders and the Suicide Probability Scale (SPS) for suicidal ideation. Results indicate that each screen most effectively assessed one clinical domain: the RDS for psychosis, the MDSIS for suicidality, and the PAS for depression. Gender differences were observed in screen items most effective for classifying inmates by suicide risk level.

This study investigated the seasonal, monthly and weekly variation of fatal suicidal behaviour in Pietermaritzburg, as well as the relationship between fatal suicidal behaviour and climate. Secondary analysis was performed on suicide data collected for two unpublished honours theses. Results indicate that there is significant monthly variation in the distribution of fatal suicidal behaviour in Pietermaritzburg, with the expected spring-summer peak and winter trough . This pattern was more pronounced for adults than for the youth or the elderly. There was no significant variation in the weekly distribution of suicide, and suicides did not reach a peak on Monday as has been evidenced in previous research. Instead, the distribution showed a peak on Sunday with a steady decrease towards the end of the week. An increase in humidity, ambient temperature and minimum temperature was associated with an increase in suicide rates . Overall this relationship was stronger for violent, than non-violent suicide. However, a significant negative relationship was found between hours of sunshine and suicide, but this was only significant for non-violent suicide. This study was largely descriptive, and further research is indicated in order to develop a theoretical framework for understanding the temporal distribution of suicide . / Thesis (M.Soc.Sc.)-University of Natal, Pietermaritzburg, 2000.

This paper aims to provide insight into the risk factors contributing to suicidal ideation and behavior among adolescents. First, the author overviews the extant academic literature on the subject. She highlights the persistently high incidence of suicide among young people in the Czech Republic and briefly defines the stages of adolescence as well as the particular forms and methods of suicidal behavior. Subsequently, the author discusses in detail individual aspects of demographics, clinical data, familial environments and interpersonal relationships that the academic literature associates with an increased risk of suicidality among adolescents. Concluding the overview, the author sets the topic of suicide into the context of a children's crisis helpline. The author goes on to present an empirical analysis of reports documenting suicidal calls made to a children's crisis helpline. She uses both qualitative and quantitative methods to identify particular life circumstances that may contribute to the development of suicidal ideation and/or behavior, paying attention to distinct aspects of suicidality and to gender differences. As part of her analysis, the author critically evaluates the benefits and pitfalls associated with the use of data obtained from an anonymous crisis helpline.

No description available.

Suicide, a public health problem on a global scale, has become the focus in many domains across the United States. With the recent push to provide solutions to the adolescent suicide rate in the U.S., the school setting has become an important venue for prevention and intervention efforts. While there are many risk and protective factors, the majority of suicide completions are concurrent with psychiatric disorders among adolescents; as such, this is an area that warrants further investigation. Additionally, school resources are often overwhelmed by the magnitude of need among the student population; therefore, effective interventions must be identified that can feasibly be implemented in the schools. Research has suggested that parent-adolescent relationships are key in the prevention of suicide, yet minimal research has been conducted towards promoting healthy parent-adolescent relationships for at-risk adolescents. Additionally, some research suggests that school and community interventions are only more effective than parental support when negative parent-adolescent relationships are present. This implies that fostering parental support should be a top priority in school-based suicide prevention efforts. This literature review identifies and summarizes pertinent scholarly research and resources for schools to better support parents of adolescents who struggle with suicidal thoughts and previous attempted suicides. As part of an intervention plan which increases home/school collaboration in adolescent suicide prevention, handouts were developed for parents (found in the appendix), which include information on warning signs of suicide, risk factors for suicide, and methods of responding to suicidality. After adapting these handouts to best meet their students' needs, school-based mental health professionals may consider including these handouts in their school's crisis plan and suicide prevention efforts.

Abstract not available

Department of Psychology, University of Newcastle. Bibliography: leaves 69-78.