A number of methods have been developed to analyze longitudinal data with dropout. However, there is no uniformly accepted approach. Model performance, in terms of the bias and accuracy of the estimator, depends on the underlying missing data mechanism and it is unclear how existing methods will perform when little is known about the missing data mechanism. Here we evaluate methods for estimating change over time in longitudinal studies with informative dropout in three settings: using a linear mixed effect (LME) estimator in the presence of multiple types of dropout; proposing an update to the pattern mixture modeling (PMM) approach in the presence of imprecision in identifying informative dropouts; and utilizing this new approach in the presence of prognostic factor by dropout interaction. We demonstrate that amount of dropout, the proportion of dropout that is informative, and the variability in outcome all affect the performance of an LME estimator in data with a mixture of informative and non-informative dropout. When the amount of dropout is moderate to large (>20% overall) the potential for relative bias greater than 10% increases, especially with large variability in outcome measure, even under scenarios where only a portion of the dropouts are informative. Under conditions where LME models do not perform well, it is necessary to take the missing data mechanism into account. We develop a method that extends the PMM approach to account for uncertainty in identifying informative dropouts. In scenarios with this uncertainty, the proposed method outperformed the traditional method in terms of bias and coverage. In the presence of interaction between dropout and a prognostic factor, the LME model performed poorly, in terms of bias and coverage, in estimating prognostic factor-specific slopes and the interaction between the prognostic factor and time. The update to the PMM approach, proposed here, outperformed both the LME and traditional PMM. Our work suggests that investigators must be cautious with any analysis of data with informative dropout. We found that particular attention must be paid to the model assumptions when the missing data mechanism is not well understood.

Utilizing longitudinal panel data from Youth In Transition Project, the Person-Environment fit (P-E Fit) theory and its specific application to the area of delinquency and aggression was investigated longitudinally. Analysis of Covariance Structure Technique (LISREL) was used to address the issues of multi-dimensionality, stability, measurement of total P-E fit and to test the proposed delinquency model. The relationships between P-E fit, psychological strain, and delinquency were tested both cross-sectionally and longitudinally . The student sub-group (those respondents who stayed in school after high school) and the working sub-group (those who went to work after high school) were tested separately. P-E fit had significant negative effect on both psychological strain and delinquency in most of the cross-sectional models. Similar results were obtained in three of the longitudinal models also . The evidence from longitudinal models tended to support the idea that the causal flow of the relationship between P-E fit, psychological strain and delinquency to be from P-E fit to both psychological strain and delinquency. The longitudinal and cross sectional relationship between P-E fit, psychological strain, and delinquency were more pronounced among the working sub-group than the student sub-group of the sample population. P-E fit tended to be quite stable during the high school years and subject to noticeable change when the transition was made to work or college environments.

The goal of the present study was to verify whether four purported risk factors predate the development of eating disorder symptoms, particularly bulimia nervosa. The four major purported risk factors for developing bulimia nervosa (and eating disorders in general) among female adolescents include: (a) over internalization of culture’s value of thinness in women, (b) inordinate dissatisfaction with body form, (c) depression, and (d) irrational beliefs and cognitions about thinness and the benefits of dieting. The present study involved a 5-year follow-up of adolescent girls initially identified as being either at high or low risk for developing an eating disorder, particularly bulimia nervosa. Subjects completed the risk factor inventories, and eating disorder diagnoses were based upon a structured Diagnostic and Statistical Manual of Mental Disorders clinical interview. Results indicated that: (a) two bulimic cases were found in the high-risk group, with an overall prevalence rate of 3.5% (2/57); (b) the total 6-month incidence rate (for any eating disorder) was 6.5% in the high-risk group, and 0.0% in the low-risk group; (c) younger at-risk girls tended to generally acknowledge more eating disorder symptoms; (d) z-score means of the low and high risk group are dramatically different at both Time #1 and 5 years later at Time l#2, with the high-risk group exhibiting more severe and quite stable symptomatology relative to the low-risk group; and (e) change in scores over time, in all four risk factor measures, was related to bulimia, binge-related symptoms, and overall (total) symptoms. The study confirmed the importance of these risk factors in the etiology of eating disorder symptoms, as well as the significance of tracking girls in early adolescence in longitudinal studies.

The primary focus of this dissertation is an empirical investigation of three approaches to the measurement of longitudinal change. For the present study, difference scores, residual change scores, and percentage gain scores are compared to determine if their use results in similar findings when the relationships between three resource areas (health, social, and financial) and subjective well-being are analyzed. The propositions which are tested were derived from current aging theories. Meta-analysis procedures were employed to synthesize past research findings in gerontology. The data which were analyzed are those of the Longitudinal Retirement History Study (LRHS), a research project sponsored by the Social Security Administration. The sample consists of 8922 continuers who participated in the 1969, 1971, and 1973 waves of data collection. Findings from the meta-analysis suggest that the correlation coefficients calculated from the LRHS data on the relationship between subjecive well-being and the areas of health resources and social resources are similar to those of other aging studies. The relationship between measures of financial resources and subjective well-being is stronger for the LRHS respondents than that reported in other aging studies. The results on the analysis of longitudinal change indicate that change in health resources and in financial resources are significant predictors of subjective well-being at a later-point-in-time and of change in subjective well-being. For the present study, change in social resources contributes little to the regression equations. The three selected approaches to the measurement of change rank individuals similarly on the construct of change. However, the use of difference scores, residual change scores, and percentage gain scores does not always result in similar findings when multivariate procedures are used. Residual change scores appear to possess a number of advantages. They tend, however, to be strongly related to the time 2 scores from which they are derived, a phenomenon not emphasized in the measurement of change literature. Improving the reliability of measures, allowing adequate time for change to occur, and using sample sizes which are large are suggested to maximize the possibility of obtaining correlation coeffecients based on change scores which are large and stable.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13230号 / 論医博第2170号 / 新制||医||1036(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中山 健夫, 教授 松田 文彦, 教授 富樫 かおり / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

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AN ABSTRACT OF THE DISSERTATION OF SARA J. W. BIEBL, for the Doctor of Philosophy degree in Child Clinical Psychology, presented on June 14th, 2010 Southern Illinois University Carbondale. TITLE: A DIATHESIS-STRESS MODEL OF VICTIMIZATION: RELATIONS AMONG TEMPERAMENT, PEER VICTIMIZATION, PSYCHOPATHOLOGY AND HEALTH PROBLEMS MAJOR PROFESSOR: Dr. Lisabeth F. DiLalla, Ph.D. Youth who are victimized by their peers are more likely to develop symptoms of psychopathology and health problems in adolescence and adulthood. Also, temperamental traits of behavioral inhibition and emotional reactivity have been found to be significant risk factors for the development of mental and physical health problems. Diathesis-stress models of psychopathology indicate that the interaction between temperament and experiences of trauma may lead an individual to develop psychopathology. Most studies using a biosocial model of psychopathology, however, have focused more on experiences of physical and sexual abuse rather than experiences of peer abuse. No studies to date have examined how experiences of peer victimization moderate the relationship between temperament and later experiences of psychopathology and health problems, which was the primary focus of the present study. A second aim of the present study was to examine how the stability of victimization throughout childhood related to health problems in adolescence. Seventy 12- to 20-year-old youth participated in the present longitudinal study. This longitudinal study included three specific time points. At time 1, when participants were five years of age, they engaged in a 20-minute peer play interaction and their parents completed temperament measures. Tapes of the peer play interaction were rated by trained coders for instances of peer victimization. During time 2, these same youth were between the ages of 10 and 18 and were contacted again and asked to complete measures related to peer victimization. Finally, at time 3, which was the present study, participants were between the ages of 12 and 20 and completed a 1-hour telephone interview which was used to obtain information about experiences of peer victimization as well as mental and physical health outcomes. Results from the present study indicated that youth with specific early temperamental traits (behaviorally inhibited and difficult) and who experienced peer victimization that is impairing appeared to be at multiplicatively greater risk for developing mental and physical health problems in adolescence compared to youth who did not have these same biological vulnerabilities and environmental experiences. Additionally, youth who chronically experienced peer victimization had significantly more mental and physical health problems than youth who experienced less stable victimization. This study adds to the current research on peer victimization by using a diathesis- stress model to examine the interactive effects of peer victimization and temperament on negative mental health and physical health outcomes. Moreover, findings from this study will provide researchers and professionals with information that can aide in the development of interventions for children who experience peer victimization and who suffer from different types of health problems and symptoms of psychopathology. More specifically, by understanding how innate factors such as temperament interact with a child's experience of peer victimization, researchers and clinicians may be able to design more specialized interventions for children based on the patterns of their victimization experiences and temperamental traits.

Depression in mothers is an important risk factor for behavioral and emotional problems in their children (Elgar, McGrath, Waschbusch, Stewart, & Curtis 2004), and disrupted parenting is thought to mediate the influences of maternal depression on children. This 4-year longitudinal study examined whether mothers’ depression predicted parenting of children with behavioral problems across the preschool years. This study attempted to tease apart the correlates of enduring, chronic maternal depressive symptoms from those of transient depressive symptoms on parenting during the preschool years. In particular, it sought to predict both changes in parenting across the preschool years as well as to predict parenting practices as parents and children emerge from the preschool years. Participants were 199 mothers of 3-year-old children, with behavior problems who completed measures of depression and parenting yearly until children were 6 years old. Mothers with higher average depressive symptoms across the preschool years reported more overreactivity and laxness, and showed less warmth when their children were 6 years old. These mothers were also more likely to increase their self-reported overreactivity over time. Increases in depression were associated with increases in overreactivity and laxness, but not in warmth. These results provide stronger evidence than previous cross-sectional studies for a causal relation between depression and parenting, and point to the importance of providing adequate treatment and support to depressed mothers of preschool children.

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