published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

published_or_final_version / Education / Doctoral / Doctor of Philosophy

This investigation examined several dimensions of personality functioning in a longitudinal sample of females. These data are part of an existing project evaluating female development across 3 different time points starting in adolescence and transitioning into adulthood. Subjects were categorized into a clinical group (females with a high degree of psychiatric comorbidity) and a normal control group. All participants were initially recruited when they were between 14-18 years of age, and were followed up twice when they were 19-23, and 24-28. In an attempt to explore possible heterogeneity in personality trait development, the research is presented as three separate studies examining the following: (1) fluctuations in mean-level and rank order stability estimates across time; (2) the validity of established personality trends relative to their association with antisocial behavior; and (3) mechanisms that may contribute to personality trait consistency across development such as neighborhood context. This is the first study to investigate personality functioning across time in females who are disturbed in multiple areas of social and psychological functioning. Results highlight the importance of considering distinct subgroups of the general population when exploring developmental trends in personality.

In modern China, air pollution has become an essential environmental problem. Over the last 2 years, the air pollution problem, as measured by PM 2.5 (particulate matter) is getting worse. My report aims to carry out a longitudinal data analysis of the air quality index (AQI) in 3 main economic zones in China. Longitudinal data, or repeated measures data, can be viewed as multilevel data with repeated measurements nested within individuals. I arrive at some conclusions about why the 3 areas have different AQI, mainly attributed to factors like population, GDP, temperature, humidity, and other factors like whether the area is inland or by the sea. The residual variance is partitioned into a between-zone component (the variance of the zone-level residuals) and a within-zone component (the variance of the city-level residuals). The zone residuals represent unobserved zone characteristics that affect AQI. In this report, the model building is mainly according to the sequence described by West et al (2007) with respect to the bottom-up procedures and the reference by Singer, J. D., & Willett, J. B (2003) which includes the non-linear situations. This report also compares the quartic curve model with piecewise growth model with respect to this data. The final model I reached is a piece wise model with time-level and zone-level predictors and also with temperature by time interactions. / text

<p>Today, health problems are likely to have a complex and multifactorial etiology, whereby psychosocial factors interact with behaviour and bodily responses. Women generally report more health problems than men. The present thesis concerns the development of women’s health from a subjective and objective perspective, as related to psychosocial living conditions and physiological stress responses. Both cross-sectional and longitudinal studies were carried out on a representative sample of women. Data analysis was based on a holistic person-oriented approach as well as a variable approach. In Study I, the women’s self-reported symptoms and diseases as well as self-rated general health status were compared to physician-rated health problems and ratings of the general health of the women, based on medical examinations. The findings showed that physicians rated twice as many women as having poor health compared to the ratings of the women themselves. Moreover, the symptom ”a sense of powerlessness” had the highest predictive power for self-rated general health. Study II investigated individual and structural stability in symptom profiles between adolescence and middle-age as related to pubertal timing. There was individual stability in symptom reporting for nearly thirty years, although the effect of pubertal timing on symptom reporting did not extend into middle-age. Study III explored the longitudinal and current influence of socioeconomic and psychosocial factors on women’s self-reported health. Contemporary factors such as job strain, low income, financial worries, and double exposure in terms of high job strain and heavy domestic responsibilities increased the risk for poor self-reported health in middle-aged women. In Study IV, the association between self-reported symptoms and physiological stress responses was investigated. Results revealed that higher levels of medically unexplained symptoms were related to higher levels of cortisol, cholesterol, and heart rate. The empirical findings are discussed in relation to existing models of stress and health, such as the demand-control model, the allostatic load model, the biopsychosocial model, and the multiple role hypothesis. It was concluded that women’s health problems could be reduced if their overall life circumstances were improved. The practical implications of this might include a redesign of the labour market giving women more influence and control over their lives, both at and away from work. </p>

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease that has a highly variable disease course. Three biologic agents, adalimumab, etanercept, and infliximab, have been developed for the treatment of AS. We conducted three studies: 1) an exploratory analysis of a year-long longitudinal dataset to gain insight into the variability of disease activity, physical function, and well-being and to explore the relationship between these outcome measures; 2) a systematic review of the available evidence for the efficacy of biologic treatment; 3) a systematic review of potential adverse effects of this treatment. We found that repeated measures of disease activity, function and well-being fluctuate considerably between patients, with complex patterns occurring over time within patients. There was mostly high quality evidence that these biologics are efficacious against placebo. We did not find evidence of an increase in serious adverse events or serious infections from short-term randomized controlled trials.

Considerable amounts of event history data are collected through longitudinal surveys. These surveys have many particularities or features that are the results of the dynamic nature of the population under study and of the fact that data collected through longitudinal surveys involve the use of complex survey designs, with clustering and stratification. These particularities include: attrition, seam-effect, censoring, left-truncation and complications in the variance estimation due to the use of complex survey designs. This thesis focuses on the last two points. Statistical methods based on the stratified Cox proportional hazards model that account for intra-cluster dependence, when the sampling design is uninformative, are proposed. This is achieved using the theory of estimating equations in conjunction with empirical process theory. Issues concerning analytic inference from survey data and the use of weighted versus unweighted procedures are also discussed. The proposed methodology is applied to data from the U. S. Survey of Income and Program Participation (SIPP) and data from the Canadian Survey of Labour and Income Dynamics (SLID). Finally, different statistical methods for handling left-truncated sojourns are explored and compared. These include the conditional partial likelihood and other methods, based on the Exponential or the Weibull distributions.

Substance use behaviours have been viewed as the end products of a combination of influences. Numerous theories for working with substance use behaviour utilizing a multi-systemic approach have been proposed. In this project, an effort was made to control for limitations and problems that have often beset previous studies utilizing such an approach. The overall objective of the current project was to test, using a multi-systemic approach, the ability of the family socialization framework to explain the development of substance use patterns in youth and young adults. The central hypothesis of this project was that family socialization factors (contextual factors) affect and predict the development of an offspring’s personality (individual factors) and substance use behaviour. The behavioural genetic approach (i.e., the adoption design) was utilized to examine the genetic and environmental impacts on associations between factors. This project used secondary data analyses of general population data to examine the links between aspects of the family environment, personality, and substance use patterns. The Vancouver Family Survey data set used here contained information on fathers, mothers, and offspring from 405 families (328 biological and 77 adoptive) at two points in time. The development of personality and substance use behaviours over time, and associations with family socialization factors, were examined through three studies. Study 1 focused on the associations between offspring’s perspectives of fathers’ and mothers’ parental socialization and offspring’s polysubstance use. Study 2 investigated the development of addiction-prone personality characteristics and the predictive effects of family socialization and demographic variables on these characteristics. Study 3 explored the subscales of the Addiction-Prone Personality scale: impulsivity/recklessness, sensation seeking, negative view of self, and social deviance proneness. The descriptive characteristics of each subscale and changes in subscale scores over time were investigated. Also examined were transgenerational associations on these subscales, and potential relationships between personality subscales and choice of substance. The results of this project suggest that family socialization may be linked with both substance use behaviour and personality development over time. Nurturing family socialization is negatively associated with the development of addiction-prone personality characteristics. It is also negatively associated with the development of substance use behaviours. These results are consistent with previous studies utilizing a family socialization framework. The findings supporting the family socialization framework are very encouraging for the field of child, youth, and family-related practice. Some of the limitations of the current project, implications of the findings, and future research directions are discussed. / Graduate

Thèse diffusée initialement dans le cadre d'un projet pilote des Presses de l'Université de Montréal/Centre d'édition numérique UdeM (1997-2008) avec l'autorisation de l'auteur.

Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of secreted proteins, which include in addition to BDNF, nerve growth factor (NGF) and neurotrophin 3-6 (NT-3-6). BDNF mediates its functions by activating two cell surface receptors, pan-neurotrophin receptor (P75NTR) and tropomyosin-related kinase B (TrkB) and their downstream intracellular cascades. BDNF is best known for its role in neuronal survival, regulation of neuronal differentiation, migration and activity-dependent synaptic plasticity. However, BDNF is widely expressed in non-neuronal tissues as well. The localization and the function of BDNF in intestinal smooth muscle cells (SMCs) are not well defined. Thus, the main purpose of the present study was the identification and characterization of BDNF in intestinal SMCs. Using xviii biochemical and molecular techniques, we have demonstrated in this study that BDNF is synthesized and released in rabbit intestinal longitudinal SMCs cultures. Furthermore, gut neuropeptides, Pituitary Adenylate Cyclase Activating Peptide (PACAP) and substance P (SP) increased BDNF expression and release in SMCs cultures after 24 hrs and 48 hrs incubation. We have also shown that intracellular Ca2+ levels are essential for SP stimulation of BDNF expression and secretion. Lastly, we have demonstrated that exogenous BDNF enhanced carbachol (CCh)-induced contraction of isolated longitudinal muscle strips, and this was inhibited by preincubation with TrkB inhibitor K252a and PLC inhibitor U73122 sugesting that BDNF sensitize longitudinal SMCs to CCh by activating PLC pathway, which is normally absent in those muscle cells. These results provide new insight into the mechanisms of neurotrophin (BDNF) modulation of gut function, which may lead to new therapeutic avenues for treatment of gastrointestinal disorders, and explain some of the pathological changes associated with inflammation such as hypercontractility associated with gut infection or IBD.