Currently there is limited research addressing the eating behaviours of preadolescent children, despite evidence suggesting that friends and peers may contribute to the developing eating attitudes and behaviours of children of this age. Eating behaviours in terms of this thesis include both under- and over- eating behaviours, with a specific focus on the under-eating behaviour, dietary restraint, and the over-eating behaviours emotional eating and external eating. The fundamental aim of this thesis was to examine friend and peer influences on children s eating behaviours, with a specific focus on a community sample of preadolescent children. Based on links established in the literature between childhood eating behaviours (dietary restraint, emotional eating and external eating) and parental controlling feeding practices (pressure to eat and restriction) and childhood symptoms of anxiety and depression, these factors were also considered alongside the contribution of friends and peers, both cross-sectionally and longitudinally. The longitudinal stability and continuity of self-reported eating behaviours and perceived parental feeding practices in preadolescent children were also examined in this thesis. A pilot study and experimental study provided an objective measure of children s snack food intake following a school lunchtime, when offered a selection (healthy and unhealthy) of snack foods in the presence of friends and peers. Links between food intake in the presence of friends and peers, and self-reported eating behaviours, parental controlling feeding practices, child symptoms of anxiety and depression and BMI were further explored. The research in this thesis suggests that friends dieting behaviours predict individual children s dieting behaviours, and also highlights links between problematic eating and anxiety in preadolescent children. Parental controlling feeding practices were found to have a negative impact on preadolescents eating behaviours and were also found to be potentially linked to the development or maintenance of anxiety and depression symptoms in children of this age. Preadolescents reports of eating behaviours and perceptions of the controlling feeding practices their parents utilised with them were stable over time, but, with the exception of restriction, lacked continuity. Dietary restraint, emotional eating and external eating decreased over a 12 month period. While some of the research in this thesis requires replication, the results present many novel and interesting findings. Using longitudinal and experimental data, the research reported on in this thesis highlights the important contributions of friends, peers, parents and individual anxiety and low mood to the eating attitudes and behaviours of preadolescent aged children.

Anxiety and depression are among the most common psychiatric disorders in childhood and adolescence (Costello, Egger, & Angold, 2005). Although the parental environment appears to play a role in the development of emotional disorders (e.g., Abramson & Alloy, 2006), cognitive styles within the families of adolescents with internalising disorders have received little attention. The main aim of this thesis was to increase the understanding of maternal cognitions in relation to internalising disorders experienced by adolescents. Specifically, maternal attributional style, catastrophic worries, selective attention and perceptions of adolescents' social competence were examined through a combination of cross-sectional, correlational and experimental designs in the programme of five studies conducted with a clinical sample. Three groups of adolescents and their mothers participated in the studies: adolescents with clinical internalising disorders, adolescents with clinical externalising disorders and a non-referred group of school-children along with their mothers. In support of the hypotheses, mothers of adolescents with clinical internalising disorders had more negative attributional biases than the mothers in the two control groups. When parental attributions were examined from the child's perspective, adolescents in the clinical internalising group perceived that their parents had more negative attributions than both control groups. Examination of maternal evaluations of adolescents' social skills, revealed that even though adolescents did not have social deficits according to objective ratings, mothers of adolescents with internalising disorders underestimated the performance of their children compared to the non-referred control group. Significant relationships were found between maternal and adolescent attributions and perceptions of social competence, suggesting a link between maternal and adolescent cognitive style. Furthermore, mothers of the clinical internalising group produced a greater number of worries which were more catastrophic in content than mothers in the control groups. Contrary to predictions, mothers of adolescents with clinical internalising disorders did not selectively attend to threatening information related to adolescents' behaviours. Analyses using combined data from the four studies that showed significant relationships provided evidence that different cognitions in mothers and their children are interrelated, highlighting the importance of interactions between various cognitions within the family. Additionally, attributional style, catastrophic worries and negative perceptions were found to discriminate families with adolescents with internalising disorders from those with adolescents with externalising disorders or non-referred adolescents. The studies included in this thesis extend the current literature on maternal cognitions and adolescent internalising disorders and suggest that mothers of adolescents with internalising disorders are characterised by cognitive biases that should be taken into consideration in both research and clinical practice.

Thesis (Ph. D.)--York University, 2000. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 123-142). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ56225

Thesis (M.S.Ed.)--Baylor University, 2007. / Includes bibliographical references (p. 180-191).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 50-65.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Interventions targeting processes that commonly maintain different psychological disorders have demonstrated promising effectiveness data. However, very few studies have examined brief transdiagnostic groups. Qualitative explorations of the acceptability of both transdiagnostic and brief groups are also very limited. A brief transdiagnostic group, the Take Control Course (TCC), has been developed for clients with common mental health problems in primary care services. This thesis examined the effectiveness and acceptability of the TCC, which is a 6-session transdiagnostic group intervention. The TCC is explicitly theory-driven and targets mechanisms of psychological change specified by Perceptual Control Theory (PCT). Three papers are presented within this thesis that examined: i) the empirical and conceptual background of the TCC; ii) whether the TCC was non-inferior compared to an active control (individual low-intensity Cognitive Behavioural Therapy, CBT); iii) whether the TCC was acceptable to participants using qualitative examination of participants’ experience of the TCC and perceptions of what contributed to psychological change (or lack of change). The thesis comprises: i) a narrative review; ii) a non-inferiority RCT; iii) a qualitative interview study using Thematic Analysis. The thesis utilised mixed methods in order to understand the TCC from multiple perspectives. The overall programme of research that the thesis is part of is strongly informed by the Medical Research Council (MRC) framework for developing and evaluating complex interventions. Although the MRC guidelines stress the utility of randomised experimental designs in evaluating an intervention, they also recognise the contribution that qualitative methodologies make to such evaluations. The narrative review outlined how the development of a transdiagnostic intervention, which targets specific transdiagnostic processes, could provide an efficient way of promoting psychological change. It explicitly detailed how the theoretical basis informed intervention components. Within the RCT, intention-to-treat analyses at 6-month follow-up found that the TCC was non-inferior to individual low-intensity CBT on anxiety and depression outcomes, functioning and an idiosyncratic problem measure. 156 clients were randomised. Secondary, per-protocol analyses, found inconclusive evidence of non-inferiority. This was the first randomised trial providing evidence for the non-inferiority of a brief transdiagnostic group compared to established individual therapy. The qualitative study of 12 in-depth interviews indicated that the flexible group format of the TCC was appreciated, as participants felt able to engage at their own pace and adapt components. Greater clarity regarding what was within participants’ control reduced distress and enabled effective pursuit of valued goals. This was the first qualitative study of participant experience of a brief transdiagnostic group. Findings indicated that TCC was acceptable and non-inferior to an established CBT intervention. This adds to the evidence base for transdiagnostic interventions.

Hippocampal neurogenesis is linked to the onset, progression and remission of major mood disorder such as anxiety and depression. Neurogenesis is the process by which new neurons are formed in the brain. Mitochondria mediate cellular adaption and provide energy to support growth of new neurons. Chronic stress and mood disorders have been associated with impairments in mitochondrial function and neuronal growth. Individuals experiencing stress and mood disorders reportedly use cannabis as a means to self-medicate. The impacts of cannabis on stress-related effects on hippocampal neurogenesis and mitochondria are vastly unexplored. To investigate these effects we generated an in vitro model of hippocampal neuron stress by treating HT22 cells with corticosterone, the major effector molecule of stress in rodents. We first characterized the impacts of corticosterone on markers of neurogenesis and mitochondrial function in HT22 hippocampal cells. We found that corticosterone decreased gene markers of neurogenesis, mitochondrial biogenesis, content, dynamics and decreased mitochondrial membrane potential. Corticosterone also decreased levels of antioxidant enzymes but did not alter levels of reactive oxygen species (ROS) or elicit lipid peroxidation. We then investigated with potential impacts of cannabis components, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), on corticosterone-induced stress. Individually, THC and CBD decreased markers of neurogenesis, dysregulated mitochondrial dynamics and decreased mitochondrial membrane potential. Interestingly, both THC and CBD increased a marker of mitochondrial biogenesis. Finally, we co-treated HT22 cells with corticosterone and THC or CBD to interrogate the impacts of THC and CBD on corticosterone-induced alterations. Our results indicated THC and CBD had no effect on corticosterone-related reductions in neurogenesis markers or mitochondrial membrane potential. However, THC demonstrated a rescuing effect on a marker of mitochondrial biogenesis and CBD normalized a marker of mitochondrial fission; both of which were decreased with individual corticosterone treatments. This thesis ultimately identifies some of the pathways THC and CBD may impact stress response in relation to neurogenesis and mitochondria. / Thesis / Master of Science (MSc) / Neurogenesis is a process that describes the production of new nerve cells in the brain. It mainly occurs during early life, but persists in a central brain structure responsible for learning and memory, known as the hippocampus, throughout our lives. This active brain structure relies on the function of certain organelles called mitochondria, which are the primary cellular energy producers and promote nerve cell production. Mood disorders, such as anxiety and depression, may result as a consequence of impaired hippocampal neurogenesis. Evidently, people suffering from anxiety and depression turn to cannabis use for management and treatment of their mood disorders. Considering cannabis has been shown to affect neurogenesis and mitochondrial function, our primary objective was to explore its effects on hippocampal neurogenesis by focusing on mitochondrial function, in the context of stress. We demonstrate that components found in cannabis, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), alter the stress-induced changes in mitochondrial functions related to neurogenesis, suggesting that cannabis may play a role in protecting nerve cells.

No description available.