Medicine & Health

Publication Search Results

Now showing 1 - 10 of 17
  • (2013) Grisham, Jessica; Williams, Alishia
    Journal Article
    The aim of the current study was to examine cognitive and psychological factors hypothesized to affect responding to intrusions in obsessive-compulsive disorder (OCD). A group of individuals diagnosed with OCD was compared to a social phobia (SP) group and a nonclinical control group. Participants performed neuropsychological tasks, completed selfreport measures, and engaged in a self-relevant thought suppression task. The OCD group demonstrated worse working memory and response inhibition and had increased intrusions during the suppression task relative to comparison groups. They also reported more distress during the task relative to the nonclinical group, but not the SP group. Regression analyses revealed that beliefs about thought control failures, but not working memory or response inhibition, was associated with increased frequency of intrusions and greater distress during suppression. Findings support cognitive-behavioural models of OCD that emphasize the role of meta-beliefs in explaining the struggle with obsessional thoughts.

  • (2013) Williams, Alishia; Lau, Gloria; Grisham, Jessica
    Journal Article
    Background and Objectives: Thought-action fusion (TAF), or maladaptive cognitions regarding the relationship between mental events and behaviours, has been implicated in the development and maintenance of obsessive-compulsive disorder (OCD). As some religions promote TAF-like appraisals, it has been proposed that religiosity may play a role in the transformation of normally occurring intrusive thoughts into clinically distressing obsessions. No research, however, has experimentally investigated the mediating role of TAF on the relationship between religiosity and OC symptoms. Methods: 85 Christian, Jewish, and Atheist/Agnostic participants were exposed to an experimental thought-induction protocol and reported on their associated levels of distress, guilt, feelings of responsibility, and urge to suppress target intrusions experienced during a 5-minute monitoring period. Participants also completed measures of obsessive-compulsive symptomatology, TAF beliefs, and general psychopathology. Results: Using PROCESS and bootstrapping analyses, a test of the conditional indirect effects of religiosity on obsessive-compulsive symptoms revealed that Christianity moderated the effects of religiosity on moral TAF beliefs, which in turn mediated the relationship between religiosity and obsessive-compulsive symptoms. Furthermore, in the Christian group, moral TAF beliefs mediated the relationship between religiosity and ratings of guilt and responsibility following the experimental protocol. Limitations: The use of university students with moderate levels of religiosity. Conclusions: Collectively the results suggest that obsessional thinking is not attributable to religion per se, but that teachings underlying certain religious doctrines may fuel TAF beliefs that are implicated in the maintenance of OCD.

  • (2010) Williams, Alishia; Moulds, Michelle; Grisham, Jessica; Gay, Philippe; Lang, Tamara; Kandris, Eva; Werner-Seidler, Aliza
    Journal Article
    Study 1 evaluated the psychometric properties of the English version of the Thought Control Ability Questionnaire (TCAQ; Luciano, Algarabel, Tomás, & Martínez, 2005), an index of perceived control over intrusive cognitions. Confirmatory factor analysis in a sample of 720 University students revealed a clear uni-dimensional structure (after removal of items 5, 7, 8, 14, and 25) with high internal consistency (α = .87, 95% CI = [.86, .88]) and test-retest reliability after a six month interval (r = .68). Correlational analyses supported an inverse relationship with measures of depression, anxiety, maladaptive cognitive control strategies, and obsessive–compulsive symptomatology. Study 2 tested the ability of the TCAQ to predict successful cognitive control during an experimental suppression protocol. Results demonstrated that weak thought control ability was predictive of the frequency and associated levels of distress of a target thought while under instruction to suppress. Additionally, weak perceived thought control ability was predictive of increased efforts to suppress the target material. Collectively, results suggest that thought control ability is a measurable individual difference variable and that the TCAQ is a reliable index of perceived cognitive control.

  • (2021) Chilver, Miranda
    Thesis
    Mental wellbeing, a state of positive subjective experience and psychological functioning, is a key component of mental health. Despite this, little is known about how mental wellbeing is manifested in the brain, or how such neural associations covary with depression and anxiety symptoms. Thus, the aim of this thesis was to explore potential electrophysiological markers of wellbeing using electroencephalography (EEG) and event-related potentials (ERPs). To facilitate further investigation into the association between electrophysiology and wellbeing, a positive psychology intervention was also developed. Following an introduction to the key topics, Chapter 2 examined the relationship between mental wellbeing and resting EEG power. This study identified a specific profile of resting EEG power that is associated with wellbeing, independent from depression and anxiety symptoms. Twin modelling clarified that this EEG profile shares a genetic correlation with mental wellbeing. Chapters 3 and 4 shift towards using ERPs to investigate how wellbeing and depression and anxiety symptoms are associated with emotional and cognitive processing. Chapter 3 reported that wellbeing was not significantly associated with emotion processing after accounting for depression and anxiety symptoms, which were significantly associated with alterations in emotion processing. In Chapter 4, no evidence was found for an association between wellbeing or depression and anxiety symptoms with cognitive ERPs, although associations with behavioural performance reported in previous studies were replicated. Finally, Chapter 5 reports on the effectiveness of an online positive psychology intervention which was found to significantly improve wellbeing, particularly subjective wellbeing. Although COVID-19 restrictions prevented the evaluation of causal links between wellbeing and EEG using this intervention, it is discussed for purposes of future research. Together, this thesis provides one of the first investigations into the electrophysiological correlates of mental wellbeing. Resting EEG power was identified as the most promising avenue for future research aiming to establish endophenotype markers of mental wellbeing, with the task-related measures assessed here were not associated with wellbeing. A short and effective online intervention was developed that could be used to facilitate future investigations into the use of resting EEG as a predictor and marker of mental wellbeing.

  • (2022) Sloane, Jennifer
    Thesis
    From a child interrupting a conversation between her parents to ask "What's for dinner?" to a nurse interrupting a physician in the middle of a complex procedure with an urgent message, interruptions are an inevitable part of our daily lives no matter who we are, where we live, or what we do. Interruptions can have a variety of affects on people's performance and behavior. While interruptions may sometimes facilitate performance, often interruptions have negative consequences. For example, interruptions may result in people making more errors or forgetting to complete a prior task altogether. This thesis examines existing strategies to help mitigate interruption costs and explores the effects of interruptions within different decision environments. Chapter I introduces the topic by discussing a few theoretical frameworks of interruptions and reviewing prior research on what makes interruptions disruptive. One strategy to minimize interruption costs is to use what is called an interruption lag, which can be thought of as taking time to prepare for a pending interruption. Chapter II presents a novel experiment to systematically explore the potential benefits of interruptions lags and an alternative intervention (i.e. providing feedback) when interruption lags are not possible. Chapters III and IV discuss the results from three experiments and a final replication study that all focus on how interruptions affect people's decision making in unique environments. The environments consist of easy problems (i.e. basic arithmetic problems) and trick problems, designed in such a way to lead the reader down an incorrect path. Results from these studies were mixed. While there was some evidence that interruptions may make people more susceptible to falling for the trick answer, this finding was inconsistent across all the experiments. Chapter V applies the findings from the previous chapters to a medical context. This chapter presents novel medical cases that were developed with the help of a medical expert. These cases consisted of easy, hard, and trick cases designed for medical students. The goals of this chapter were to validate the cases and to investigate the effects of interruptions within the different case types. The final chapter (Chapter VI) concludes with a general discussion of the experimental findings, the theoretical implications of the results, and the broader implications of this research for the field of medicine.

  • (2022) Jamshidi, Javad
    Thesis
    Wellbeing, a key aspect of mental health, is defined as a state of positive subjective experience and optimal psychological functioning. This thesis presents a series of studies devised to comprehensively explore phenotypic, genetic, and neural correlates of wellbeing. The first study (Chapter 2) aimed to compare the heritability and stability of different wellbeing measures in the TWIN-E dataset (N~1600) to discern the most suitable approach for measuring wellbeing for subsequent gene discovery efforts. This twin-based study concluded that multi-item measures of wellbeing such as the COMPAS-W scale, were more heritable and stable than single-item measures. Wellbeing-associated variants were identified via genome-wide association studies (GWAS) and highlighted the need for larger sample size. The subsequent studies were conducted using population-scale data from the UK Biobank comprising ~130,000 participants with phenotypic and genetic data. Thus, in Chapter 3, I constructed a multi-item “wellbeing index” measure using UK Biobank data to investigate its relationship phenotypically and genetically (using GWAS, polygenic scores and LD score regression) with negative mental health indicators (e.g., neuroticism and loneliness), childhood maltreatment and psychiatric illness. I confirmed that SNP-heritability of wellbeing index was higher than both single-item measures and estimates previously reported (SNP-h2 = 8.6%). Moreover, I provide an overview of phenotypic and genetic correlations between wellbeing index and negative mental health indicators. In addition, childhood maltreatment and psychiatric illnesses were associated with reduced wellbeing, with evidence that genetic factors may influence their correlations. In Chapter 4, I investigated the genetic and phenotypic associations between wellbeing index and brain structure, using magnetic resonance image-derived phenotypes from the UK Biobank. This study found associations between wellbeing and volumes of brainstem, cerebellum and subcortical regions, and structural morphology of various cortical regions. Thus, wellbeing is associated with complex structural variations, each with a small effect. Together, this thesis explores the multifaceted nature of wellbeing, elucidating its phenotypic and genetic relationships with related phenotypes, childhood maltreatment, and psychiatric outcomes, and provides novel insights into the associations between wellbeing, its genetic signatures and brain structure.

  • (2022) Shvetcov, Artur
    Thesis
    Rodents learn to fear a stimulus (e.g., a light) that signals the imminent arrival of an innate source of danger (typically an aversive foot shock). They also learn to fear a stimulus (e.g., a noise) that signals a learned source of danger (e.g., the already conditioned fear-eliciting light). Following Pavlov (1927), the former type of fear is termed first-order conditioned fear, because the stimulus is paired with an aversive unconditioned stimulus (US). The latter is termed second-order conditioned fear, because the stimulus is paired, not with a US, but with an already conditioned stimulus. There are both commonalities and differences in the neural substrates underlying these two forms of fear. Both require neuronal activity in the basolateral amygdala complex (BLA), including activation of NMDA receptors, for their encoding, and both require CaMK signalling, gene expression and DNA methylation for their consolidation. However, de novo protein synthesis is required for consolidation of first-order fear but not for consolidation of second-order fear.

  • (2022) Aung, Htein Linn
    Thesis
    With widespread access to combination anti-retroviral therapy (cART) and HIV suppression, life expectancy among people living with HIV (PLHIV) is increasing more than ever. According to UNAIDS, there were 8.1 million older PLHIV (i.e., 50 years of age and over) in 2020 globally. Although HIV-associated dementia has become rare in the cART era, mild neurocognitive impairments remain prevalent among PLHIV (~30% in virally suppressed). With aging, there is an increasing concern that HIV may precipitate neurocognitive abnormal aging because HIV is associated with increased markers of aging (e.g., immunosenescence and hyper-coagulopathy) and multiple age and HIV-related comorbidities (e.g., cardiovascular diseases). Importantly, these comorbidities occur at an earlier age and at a higher rate among PLHIV compared to age-matched HIV-negative persons. Earlier, more severe and more rapidly progressing neurocognitive impairment would have major public health consequences for the millions of PLHIV and the healthcare system. The overarching aim of this PhD thesis is to determine whether having chronic stable HIV infection and suppressive ART is associated with abnormal cognitive aging including premature cognitive aging (HIV and age synergistically/addictively lead to much lower cognitive performance at a younger age compared to controls), accentuated cognitive aging (HIV and age synergistically/addictively lead to much greater prevalence and severity of neurocognitive impairment), and/or accelerated cognitive aging (HIV and age synergistically/ addictively lead to much more rapid progression of neurocognitive impairment). To address these questions, we used a range of scientific methodologies including a systematic review, and several types of advanced statistical analyses using national and international longitudinal cohort data. First, to contextualise the potential public health consequences of cognitive aging in PLHIV, we conducted a narrative review of the burden of established dementia risk factors among PLHIV. We identified that the burden of several major dementia risk factors is much greater among PLHIV than in the general population. Second, we conducted the first-ever systematic review evaluating the current evidence for premature, accentuated and accelerated cognitive aging among PLHIV. We determined moderate evidence for premature cognitive aging and strong evidence for accelerated cognitive aging, while accentuated cognitive aging had not been optimally assessed. Lastly, addressing the previous literature major limitations (low sample size, cross-sectional study design, low proportion of older PLHIV, and inadequate controls/norms), we quantified the profiles of cognitive aging in four longitudinal studies of PLHIV. We demonstrated robust trends for premature cognitive aging among PLHIV compared to age-matched HIV-negative persons. We also demonstrated that older PLHIV had a higher risk for both neurocognitive impairment and neurocognitive decline compared to younger PLHIV, while controlling for normative age effect. These results are indicative of both accentuated and accelerated aging, although our research identified the need for longer-term studies using very large sample size to assess these trends especially in PLHIV older than 70+. Based on these findings, we discussed implications for clinical practice and future research directions.

  • (2022) Joubert, Amy
    Thesis
    Targeting and reducing the processes underlying the development and maintenance of depression and anxiety disorders, such as repetitive negative thinking (RNT), is a promising approach suggested to improve the efficacy and durability of psychological treatment. Delivering treatment online overcomes many of the barriers to accessing mental health treatment and improves treatment coverage. This thesis therefore involved the development and evaluation of a novel internet-delivered treatment targeting RNT. Study 1 involved an online qualitative survey to gain insight into how individuals define, experience, and understand rumination and worry. The findings from Study 1 were used to inform the development of the online intervention evaluated in subsequent chapters. Study 2 outlines the pilot evaluation of the online intervention. The results of Study 2 demonstrated the preliminary efficacy and acceptability of the intervention in adults, with significant reductions in participants self-reported levels of RNT, rumination, and worry, as well as symptoms of depression and generalised anxiety. Treatment effects were maintained at 1-month follow-up. Study 3 aimed to extend these preliminary findings using a randomised controlled trial design and compared the intervention when it was delivered with and without clinician guidance to a treatment-as-usual (TAU) control group. Participants in both the clinician guided and self-help groups had significantly lower levels of RNT, rumination, and worry, as well as symptoms of depression and anxiety compared to TAU at both post-treatment and 3-month follow-up. Treatment effects were significantly larger in the clinician guided group compared to self-help. This thesis provided the first evidence that targeting rumination and worry, both types of RNT, using an online intervention is efficacious, feasible, and acceptable in adults. This thesis also provided the first direct comparison of treatment outcomes and adherence between guided and self-help intervention formats and, in doing so, is the first to demonstrate the superiority of the clinician guided format. These findings add to the growing body of literature suggesting that internet-delivered interventions can successfully simultaneously target rumination and worry and that doing so is associated with significant improvements in depression and anxiety symptoms.

  • (2021) Evans, Holly
    Thesis
    Talking about dying can be distressing, but for young people with incurable diseases like cancer, talking about their needs and wishes at end-of-life is critical for achieving the best possible outcomes for patients and their families. There is a gap in the literature on factors influencing individual differences in how young people talk about death. To address this gap, this thesis examines the relevance of attachment theory in this context. Across five experiments using explicit and implicit measures, this research manipulated awareness of attachment figures prior to imagining end-of-life scenarios in order to examine the impacts of attachments on how end-of-life conversations are approached. Experiment 1 examined whether a mortality salience induction influenced how young people felt when talking about end-of-life. Experiment 2 assessed whether an attachment induction influenced how young people felt when talking about death. Experiment 3 replicated the design of Experiment 2, with the addition of measures to determine whether the attachment induction influenced what young participants chose to talk about. Experiment 4 examined whether young people who are avoidantly attached experienced a simulated end-of-life conversation differently to securely attached individuals, and whether there were differences between these groups on the topics mentioned in these end-of-life conversations. Experiment 5 used the same design as Experiments 2 and 3 but tested whether the attachment induction influenced how young people talk about the death of a close person. Across experiments, priming attachment awareness appeared to play a role in young people’s engagement with end-of-life conversations, with this relationship appearing to be moderated by individual attachment style. Further, attachment style seemed to influence the content of these simulated end-of-life conversations among young people. Individual differences in openness to discussing difficult topics such as death based on individual attachment style should be expected. These results suggest that consideration of attachment theory may have an important role to play in outcomes around end-of-life for young people and their families.