Melbourne School of Psychological Sciences - Theses
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ItemAn investigation of family-centred service in the rehabilitation of paediatric acquired brain injury( 2022)Paediatric acquired brain injury (ABI) can have significant impacts on children, adolescents, and their families. Family-centred service is considered best practice in paediatric rehabilitation and emphasises the importance of supporting families and involving them in care planning, implementation, and evaluation. However, there are varied definitions and approaches to delivering family-centred service, family needs are often unrecognised and unmet in rehabilitation, and there is a lack of research evidence informed by the lived experience of families. The aim of this program of research was to develop a better understanding of family-centred service within paediatric ABI rehabilitation. The first part of this project was a scoping review of programs involving the families of children/adolescents with ABI. Information about the programs was synthesised to develop an understanding of how families are involved in ABI rehabilitation programs. The second part of this project explored subjective experiences of family-centred rehabilitation from the perspectives of children and adolescents with ABI, their families, and rehabilitation clinicians. Two qualitative studies were conducted in the context of a state-wide paediatric rehabilitation service. Across the two studies, thirteen rehabilitation clinicians, ten parents/caregivers, five siblings, and four children/adolescents with ABI participated in semi- structured interviews, and data were analysed using constructivist grounded theory methods. The findings yielded three manuscripts, one of which has been published in a peer-reviewed journal, with the remaining two submitted to journals and currently under review. Collaboration between clinicians and families during rehabilitation was identified as central to family-centred service, with participants reflecting on how this collaboration changes over time. The importance of clinicians developing an understanding of families and their unique lives following paediatric ABI was highlighted, as was the value of hearing children’s and adolescents’ voices during rehabilitation. The key role of clinicians was also emphasised, and participants recognised that the implementation of family-centred service requires active input and facilitation from clinicians. The findings contribute novel insights into family-centred service within paediatric ABI rehabilitation, with practice recommendations to support the implementation of this approach in practice. Keywords:
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ItemNeighbourhood disadvantage and internalising symptoms in adolescents: the mediating role of stressful life events, temperament, and maternal aggression( 2013)Purpose of the study: Disadvantaged neighbourhoods are associated with increased risk for anxiety and depression in adolescents. However the mechanisms for this relationship are not fully understood. Using a longitudinal design, I investigated whether several potential mediators, including stressful life events, maternal aggressive, dysphoric and positive behaviour, and adolescent temperament (Surgency, Negative affectivity, Effortful Control, Affiliation), could help explain the relationship between neighbourhood disadvantage and symptoms of anxiety and depression in early- to mid-adolescence. Method: A community sample of 245 adolescents and their parents participated in a range of assessments at baseline (age approximately 12-13 years old), including an observational assessment of parent-adolescent interactions, and a battery of adolescent-rated questionnaires. Neighbourhood disadvantage was assessed by combining Postal Area data collected during this first wave of assessment with a measure of disadvantage called the Socio-Economic Indexes For Areas (SEIFA) developed by the Australian Bureau of Statistics Adolescents were followed-up approximately 4 years later and completed questionnaires assessing depressive and anxious symptoms. Results: Analyses revealed that adolescents from disadvantaged neighbourhoods were more likely to report a greater number of stressful life events, and depressive and anxious symptoms. They were also more likely to score higher on temperament measures of Negative Affectivity, and lower on measures of Surgency and Effortful control. Mothers from disadvantaged neighbourhoods were more likely to display aggressive and dysphoric behaviour for longer periods, and positive behaviour for shorter periods, however no differences were detected in regard to the frequency of these behaviours. Mediational analyses using a bootsrapping approach determined that stressful life events and three temperament dimensions (low Surgency, low Effortful Control, high Negative Affectivity) significantly mediated the relationship between neighbourhood disadvantage and symptoms of anxiety and depression at baseline. Stressful life events and maternal aggression significantly mediated the relationship between neighbourhood disadvantage and change in depressive and anxious symptoms from baseline to follow-up. Conclusion: The research reported in this thesis provides evidence that disadvantaged neighbourhoods differ from less disadvantaged neighbourhoods in several different ways. In addition, various factors were found to partially mediate the relationship between neighbourhood disadvantage and anxiety and depression at different periods during adolescence. Temperament appears to be important earlier in adolescence, maternal affective behaviour seems to be important during mid- to later-adolescence, while stressful life events appear to act throughout adolescence. These findings suggest that the neighbourhood environment is likely to influence adolescents both directly, and indirectly through its effects on more proximal and individual risk factors. It was concluded that prevention and intervention programs targeting a range of risk factors in adolescents from disadvantaged neigbourhoods could be particularly effective at reducing the prevalence of internalising disorders in adolescents.
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ItemChildhood maltreatment and structural neuroanatomy as risk factors for adolescent onset depression( 2012)This thesis concerns three broad subjects – childhood maltreatment, structural neuroanatomical features in early adolescence, and depressive symptoms in mid-adolescence – with the aim of examining predictive relationships between them. The core focus of the thesis was on investigating relationships between the volumes of key brain structures implicated in emotion regulation, and adolescent onset depression. The measurement of brain structures in a psychiatrically healthy sample of children aged 11-12 years, and the use of these measurements to predict onset of depressive symptoms 2-3 years later, allowed for contribution to theoretical debate about the timing of structural alterations previously associated with depression – specifically, whether observed alterations formed risk factors for depression, or whether they were outcomes of disease-related processes. The evidence of premorbid structural alterations demonstrated by this thesis suggests that there are vulnerability biomarkers for depression, and may assist in better understanding the mechanisms of depressive illness as well as identifying individuals at risk. The secondary focus of the thesis was on retrospectively examining relationships between maltreatment in childhood and structural neuroanatomical features in adolescence, with the aim of identifying effects of childhood adverse experience on brain development. Previous studies have largely utilised adult populations with maltreatment-related psychiatric illness, and therefore have not been able to conclude whether structural alterations following childhood maltreatment only occur in those individuals who later develop psychopathology, or whether these changes occur before the onset of any psychopathology. This thesis investigated whether structural changes were associated with childhood maltreatment in a healthy sample of young adolescents, allowing the separation of early experiential effects from later psychopathological processes. This research also explored whether the volumes of selected brain structures mediated relationships between childhood maltreatment and adolescent onset depression, however no such relationships were detected. As this was an exploratory measure secondary to the key themes of the thesis, and interpretations were constrained by issues of sample size, it is not dealt with in detail. The most robust aspect of this research design was the examination of neurostructural risk factors for depression, and this formed the central content of the thesis. There is also a large extant body of research and literature on depression and brain development, from which to gain a strong theoretical grounding on the role of each brain structure examined in terms of the cognitive and affective processes it is thought to subserve. For this reason, material on the epidemiology and neurobiological models of depression form the first three chapters. An exploration of the emerging body of literature on the relationships between childhood maltreatment and brain development is contained subsequently. Chapter 1 provides an introduction to the epidemiology and selected etiological influences on adolescent depression. Chapter 2 gives an overview of the current understanding of brain development in adolescence, and describes some of the key theoretical models linking brain development to adolescent onset depression. Key structures highlighted in these models were selected for investigation within this thesis, and detailed examination of the evidence and resultant hypotheses for each of five selected structures’ relationships with depression is contained in Chapter 3. The focus then turns to childhood maltreatment as a second major contributor to adolescent onset depression; Chapter 4 summarises research on the prevalence and types of childhood maltreatment and the relationships between childhood maltreatment and adverse outcomes including the development of depression. Chapter 5 reviews literature from the emerging field of developmental traumatology, drawing inferences from the body of work examining neuroendocrinological sequelae of childhood maltreatment and bringing together preliminary findings from a range of sources to form hypotheses regarding potential relationships between childhood maltreatment and the brain structures discussed in previous chapters. Chapter 6 gives detail on the design and methodology of the thesis, and Chapter 7 explains the data analysis used and reports on the results. Interpretation of findings, discussion of strengths and limitations of the research, and implications for future work are contained in Chapter 8.
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ItemGetting to the heart of teen depression: the relationship between depression and cardiovascular risk in adolescents during wakefulness and sleep( 2013)Depression has been identified as an independent cardiovascular risk factor in adults, where its presence results in higher rates of mortality and adverse cardiac events in patients with and without known cardiovascular disease (CVD). Recent literature suggests preclinical signs of cardiovascular risk are also present in adolescents experiencing depressive symptoms, however little is known about the effects of adolescent clinical depression on cardiovascular health. Moreover, no study has investigated the cardiovascular functioning of clinically depressed individuals during sleep, a state which involves cardiovascular changes including the characteristic decrease or ‘dip’ in blood pressure (BP). The aim of this study was to determine whether clinical depression is associated with an increased risk of cardiovascular disease in otherwise healthy adolescents. Experiment One sought to examine cardiovascular functioning during quiet wakefulness. Participants (n = 889, 352 male) aged 12-18 years were recruited from Victorian secondary schools in the general community. Subsequent to completing mood questionnaires and clinical interviews, 50 eligible participants (25 [6 male] clinically depressed, 25 [6 male] control) took part in a morning cardiovascular assessment at the University of Melbourne. Variables assessed included automatic clinical and continuous beat-to-beat finger arterial BP, heart rate (HR), endothelial functioning, pulse transit time (PTT), as well as cholesterol, glucose and glycohaemoglobin levels. In addition, the cumulative risk of present modifiable risk factors such as smoking was calculated according to the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) risk score, which has been shown to predict coronary calcification in young populations. It was predicted that, compared to controls, depressed adolescents would show evidence of a number of early pathophysiological processes. As hypothesised, between-group analyses revealed depressed adolescents had significantly poorer endothelial functioning, which resulted in decreased vasodilation, and shorter PTT suggesting deterioration in vascular integrity and structure. Depressed adolescents also presented with higher fasting glucose and higher triglyceride levels compared with controls. Furthermore, risk score calculations revealed significantly higher PDAY risk scores in the depressed group indicative of increased engagement in unhealthy behaviours and a higher probability of having advanced atherosclerotic lesions. Contrary to predictions however, no significant differences were found in BP or HR measurements. In order to have a more complete understanding of the cardiovascular health of depressed adolescents, Experiment Two was designed to asses BP and HR during sleep. The BP profile at sleep onset was of particular interest as a blunted decline in BP is associated with target organ damage and increased cardiovascular risk. A subgroup of female participants (8 clinically depressed, 10 control) who completed Experiment One also participated in an overnight cardiovascular assessment. Whole-night polysomnography was conducted with continuous beat-to-beat finger arterial BP and HR monitored via Portapres and ECG, respectively. Data were analysed as an average of the first 6 hours of sleep as well as 2-minute epochs of stable sleep averaged within sleep stages. Further analyses of 30-second epochs were averaged across the pre-sleep wakefulness and the first ≥5 minutes of continuous stable Stage 2 in the sleep onset period. Analyses revealed that although no significant group differences in BP or HR were found during morning wakefulness, depressed adolescents presented with higher systolic, diastolic and mean arterial BP across the whole night and across sleep stages. The difference between groups (~11 mmHg) was found to not only be statistically but also clinically significant. Depressed adolescents also displayed a blunted systolic BP decline at sleep onset compared with controls. This heightened nocturnal BP and blunted decline represent early changes in BP regulation and could be a preclinical marker for depressed adolescents at high risk of cardiovascular disease. A number of plausible mechanisms may explain the heightened BP including a failure to shift to parasympathetic dominance during sleep, increased cortisol levels as a result of a dysregulated hypothalamic-pituitary-adrenocortical axis, and limited vasodilation at night due to endothelial dysfunction as found in Experiment One. Although the mechanisms are still unclear, the results suggest that depression has a significant adverse effect on the cardiovascular system in the early stages of life. Given that risk factors are known to continue to adulthood, the heightened nocturnal BP, increased triglyceride and vascular changes may increase risk for future cardiovascular problems such as hypertension. Identification of those at high-risk and intervention should therefore be actioned as early as adolescence as a way to decrease the prevalence and global burden of CVD.