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Exploring the dynamic nature of suicidal ideation and its associated factors
Get PDFBackground: Suicide is a major global public health concern, resulting in over 720,000 deaths annually, with an estimated 20 suicide attempts for every suicide death worldwide. In the UK, approximately one in five adults report experiencing suicidal ideation at some point in their lives, with a significant proportion reporting past suicide attempts. The high prevalence of suicidal ideation has positioned it as a primary focus of research and clinical intervention, aiming to prevent its progression to suicidal attempts and eventual death. Suicide is widely recognised as a complex phenomenon arising from the interplay of biological, psychological, social, and environmental factors. To advance our understanding of suicidal behaviour, it is essential to investigate the psychological processes underlying suicidal ideation and suicide attempts. Despite extensive research that incorporates both theoretical frameworks and empirical investigations, our ability to predict and prevent suicide remains limited. Key shortcomings in current research include a lack of insight into the short-term fluctuations in suicide risk and insufficient attention to the multidimensional nature of suicidal ideation. Furthermore, while qualitative approaches can provide rich and complementary insights into the lived experience of suicide risk, the field remains predominantly focused on quantitative methodologies.
Aims: The current thesis aimed to investigate suicide risk by examining psychological factors within the overarching framework of the Integrated Motivational-Volitional model, supplemented by insights from the self-regulation perspective, with a central focus on fluctuations in suicidal ideation. Specifically, it addressed three overarching aims: (1) To what extent is suicidal ideation a dynamic process? (2) What factors are associated with different patterns of suicidal ideation? (3) With a particular focus on cognitive reactivity and ego depletion, what psychological factors are associated with suicidal ideation and suicide attempts?
Methods: To develop a comprehensive understanding of suicide risk, this thesis comprised three distinct studies employing diverse methodologies. First, a systematic review was conducted using a narrative synthesis approach to examine dynamic indicators of suicidal ideation and their associated factors, across different pattens of dynamic association and assessment frequencies (Chapter 2; 112 studies from 109 articles included in the synthesis). Next, a cross-sectional online survey was administered to a general population sample of adults living in the UK, recruited through opportunity sampling. This study explored psychological factors (e.g., entrapment, impulsivity, depression, resilience, and mindfulness) in relation to suicidal ideation and suicide attempts, as well as parameters of suicidal ideation (i.e., frequency, duration, and intensity), with a particular focus on the effects of cognitive reactivity and ego depletion (Chapter 3; N = 312; Mage = 28.44, SD = 10.0; 80.4% White; 64.7% Female). Furthermore, a subsample of survey participants with a history of suicidal ideation and suicide attempts was drawn to examine the role of cognitive reactivity and ego depletion in the relationship between entrapment and suicidal ideation through mediation analyses (Chapter 4; N = 269; Mage = 28.50, SD = 10.06; 82.9% White; 66.5% Female). Building on insights from the preceding chapters, the final study used Interpretative Phenomenological Analysis to explore individuals’ lived experiences of fluctuations in suicidal ideation in the context of their daily lives (Chapter 5; N = 10; 6 females, 4 males; Mage = 28; age range = 20 to 36 years).
Results: The systematic review (Chapter 2) indicated that suicidal ideation fluctuates significantly over periods ranging from hours to days. On average, suicidal ideation exhibited substantial within-person variability, alongside small to moderate instability (i.e., changes in suicidal ideation between consecutive time points) and temporal dependency (i.e., the carryover effect where prior levels of suicidal ideation influenced subsequent time points). The complex nature of suicidal ideation was further emphasised by its associations with a range of psychological and contextual factors, which varied based on the dynamic pattern examined (i.e., concurrent, prospective, and time-invariant associations) and the frequency of assessment (i.e., multiple times per day, once per day, and every few days per week). These findings were supported and extended by the qualitative investigation from a lived experience perspective (Chapter 5). Four group themes were identified, with ‘Fluctuating Suicidal Ideation’ as the overarching theme, reflecting a shared recognition of the dynamic nature of suicidal ideation. Three additional group themes captured the experiential features and individuals’ interpretations of these fluctuations: ‘From Whisper to Scream’ described variations in intensity and duration; ‘Whole vs. Part: Timescale and Perspective’ highlighted how shifts in timescale and perspective influenced individuals’ interpretations; and ‘Breaking the Balance’ depicted circumstances that disturbed psychological stability, resulting in heightened emotional distress and increased vulnerability to suicidal ideation. Results from the cross-sectional online survey indicated that, while most psychological factors under investigation significantly distinguished between individuals with different suicidal histories (i.e., no history, ideation only, suicide attempts) in univariate models, only impulsivity (SI vs. SA) and depression (NH vs. SA, SI vs. SA) remained significant predictors in multivariate models. Additionally, most psychological factors were individually associated with all three parameters of suicidal ideation; however, only a few predicted its frequency and duration after controlling for depression. In contrast, intensity was independently predicted by most factors, except for impulsivity and some subcomponents of cognitive reactivity (Chapter 3). Results from the mediation analyses (Chapter 4) showed that entrapment fully mediated the relationship between cognitive reactivity and suicidal ideation. The relationship between entrapment and suicidal ideation was partially mediated by ego depletion, as measured by self-regulatory fatigue, but not by depletion sensitivity.
Conclusion: This thesis contributes to the existing literature by demonstrating that suicidal ideation is not a static state, but rather a fluctuating process shaped by dynamic interactions between internal and external factors in daily life. Both quantitative and qualitative evidence support these findings, with the latter emphasising the role of distraction and a key aspect of personal construct in living with suicidal ideation (i.e., the tendency to integrate experiences to foster meaning-making). Additionally, the thesis findings also highlight the challenges of predicting more dynamic aspects of suicidal ideation, such as frequency and duration, within a cross-sectional online survey. This underscores the need for further research that examines the multidimensional nature of suicidal ideation in greater depth. The findings also demonstrated the effect of cognitive reactivity and ego depletion on the suicide risk, with a particular emphasis on how incorporating a self-regulation perspective can improve our understanding of the process of suicide risk. In light of the thesis findings, clinical treatments and interventions are encouraged to adopt a dynamic perspective that is flexible, tailored to the individual, and sensitive to fluctuations in suicide risk, while also incorporating effective coping strategies. Treatment could benefit from targeting specific aspects of suicidal ideation while also focusing on long-term goals across cognitive, emotional, physiological, and behavioural domains to reduce individuals’ baseline vulnerability, in addition to addressing acute suicidal crisis. Replication of these findings is needed to strengthen their generalisability. A deeper understanding of suicide risk may be achieved through meta-analytic research on factors associated with dynamic patterns of suicidal ideation, as well as fine-grained investigations into the various dimensions of suicidal ideation
Role of ER stress in vascular dysfunction and damage during hypertension
Get PDFHypertension is a major risk factor for cardiovascular diseases and involves complex molecular mechanisms that are not fully understood. Recent evidence indicates that endoplasmic reticulum (ER) stress plays a crucial role in hypertension, particularly by affecting vascular function. This thesis explores the hypothesis that ER stress contributes to hypertension through mechanisms involving oxidative stress, calcium signalling dysfunction, and changes in microRNA (miRNA) expression. These processes can lead to increased vascular contractility, which may ultimately contribute to elevated blood pressure.
This study utilised both human vascular smooth muscle cells (VSMCs) and animal models to investigate the molecular mechanisms linking ER stress to hypertension. Using miRNA microarray analysis, 242 differentially expressed (DE) miRNAs were identified when comparing VSMCs from hypertensive (HT) individuals to those from normotensive(NT)individuals, each represented by one sample derived from three different individuals. These (DE) miRNAs were associated with key genes and proteins related to oxidative stress and calcium signalling, including Noxs, SOD2, catalase, and ER calcium channels, as determined through Ingenuity Pathway Analysis (IPA). Notably, ER stress induced by tunicamycin significantly altered the expression of oxidative stress markers (Noxs, SOD2,catalase) and calcium channels in HT VSMCs compared to NT VSMCs, indicating that ER stress regulates oxidative stress and potentially contributes to calcium signalling dysfunction.
Further insights were gained from studying a chronic Ang II-induced hypertensive mice model (LinA3). ER stress was found to specifically activate the PERK pathway, indicating selective ER stress activation in VSMCs under hypertensive conditions. In this model, oxidative stress was characterized by increased O2 -• generation, lipid peroxidation, irreversible protein oxidation, and altered antioxidants system of VSMCs compared to wild-type mice. The role of Nox4 in modulating the interaction between oxidative stress and ER stress was highlighted, as Nox4 deficiency led to changes in the expression of ER stress markers, including increased BIP and Chop in the kidneys of wild-type mice and increased PDI in the kidneys of LinA3 mice. These findings suggest a potential roleforNox4 in modulating ER stress in hypertension.
This study found that the pre-hypertensive factor endothelin-1 (ET-1) induces ER stress and that ER stress contributes to vascular hypercontractility, using spontaneously hypertensive rats (SHRSP) compared to normotensive Wistar Kyoto (WKY) rats. Our findings demonstrated elevated levels of ER stress in the hearts and VSMCs of SHRSP compared to normotensive controls, indicating a link between ER stress andhypertension.ET-1 was found to induce ER stress through both ETA and ETB receptors, leading to increased expression of ER stress markers such as ATF4, XBP1s, and BIP. Inhibition of ER stress resulted in reduced activation of the contractile machinery, establishing a connection between ER stress, calcium signalling dysfunction, and the enhanced contractile response observed in hypertension.
Lastly, in vivo treatment with the ER stress inhibitor 4-phenylbutyric acid(4PBA)in spontaneously hypertensive rats (SHR) demonstrated reduced blood pressure, improved endothelial function, and a tendency toward improved vascular structure. These findings suggest that ER stress is a critical mediator of vascular dysfunction and structural changes in hypertension and present ER stress inhibition as a potential therapeutic strategy for managing hypertension.
In conclusion, this thesis highlights the role of ER stress in mediating vascular dysfunction in hypertension, emphasizing its interactions with oxidative stress, calcium dysfunction, and the potential involvement of miRNA regulation. These findings lay the ground work for the development of novel therapeutic strategies targeting ER stress to treat hypertension
Capture of near-Earth asteroids using multiple spacecraft
No full textAbstract not currently available
Sociological analysis of the forms of collective actions by sexual and gender minorities in Bangladesh and West Bengal
Get PDFThis thesis critically examines the collective actions of sexual and gender minorities in Bangladesh and West Bengal (Within India), particularly focusing on non-governmental organisations (NGOs) and the dynamics within lesbian, gay, bisexual and transgender and more (LGBT+) communities. The project is rooted primarily in sociology, incorporating ethnographic methods for specific aspects. It uses several methods to observe five different organisations and two social media groups that are not only located in metropolitan cities but also outside the big cities, which is often overlooked in academic research literature. Through exploring queer celebration events, social media spaces, and narratives of resource mobilisation to create a collective agency, this thesis highlights both solidarity and internal discrimination in overcoming stigma and oppression. Tensions arise from oppressive regimes, religious dominance, conflicting pressures of global LGBT+ advocacy and local socio-cultural contexts, often leading to exclusion and division. Despite a rich pre-colonial history of diverse gender and sexual identities, the current framing of LGBT+ rights as opposed to religion perpetuates misconceptions and limits effective collective action. However, emphasising local culture, religious reconciliation, and the resilience of queer labour, friendship, and care offers pathways to address resource gaps and foster creative agency within these communities
Towards an enhanced understanding of suicide risk through the lens of the Integrated Motivational-Volitional (IMV) Model of Suicide
Get PDFBackground and Aims: This thesis investigates the complex interplay of a range of psychological factors implicated in suicide risk, including multidimensional perfectionism, childhood trauma, and self-discrepancies within the context of the Integrated Motivational-Volitional Model (IMV) of Suicide. Although perfectionism, defined as striving for flawlessness and setting exceedingly high standards while being concerned about others’ evaluations, has been linked to suicide risk, the mechanisms and contextual factors underlying this relationship still require further investigation. It is also worth investigating the extent to which childhood trauma and self-discrepancies relate to established correlates of suicide risk, such as defeat and entrapment, within the IMV model’s framework. Therefore, this thesis set out to address these gaps by considering perfectionism, childhood trauma and self-discrepancies as pre-motivational risk factors. In addition, it aims to systematically explore the moderators and mediators of perfectionism (as a pre-motivational risk factor) and suicide risk relationship. Finally, by integrating Self-Discrepancy Theory within the IMV model’s framework, this research aims to better understand how different cognitive appraisals are associated with suicidal ideation.
Methods: This thesis consists of a series of studies that combine a systematic review (41 studies) and three empirical studies (N=579, N=579, N=529 participants, respectively). The systematic review searched nine databases, and it had the specific aim of identifying the mediators and moderators of the relationship between perfectionism and suicide risk. Building upon the systematic review, three empirical online studies with cross-sectional designs were undertaken with UK community-based samples. Multivariate analyses, including regression-based mediation and moderation analyses (utilising Hayes’ PROCESS Macro), were applied to test the pathways and interactions depicted in the IMV model. These analyses focused on the key roles of defeat, fear of humiliation, and internal/external entrapment in the pathway to suicidal ideation.
Results: The systematic review (Chapter 2) identified 41 potential mediators and 20 moderators that either elucidate or modify the trajectory from perfectionistic strivings/concerns to suicide risk. In Chapter 3, there was evidence that perfectionistic concerns and childhood trauma were associated with internal and external entrapment directly, and indirectly, via defeat and fear of humiliation. Although defeat emerged as a stronger mediator overall in the relationships of perfectionistic concerns and childhood trauma with internal/external entrapment, fear of humiliation indirect-only mediated relationships of perfectionistic strivings and childhood trauma with external entrapment and partially mediated the relationship between perfectionistic concerns and external entrapment. As expected, ruminative flooding moderated the relationships between defeat, fear of humiliation, and external entrapment, but not internal entrapment. The mediating roles of internal/external entrapment were consistently found to be significant in all the conceptual models in Chapter 4. However, contrary to the hypotheses, the potential moderating roles of goal adjustment factors, thwarted belongingness, and perceived burdensomeness were not significant. Finally, in Chapter 5, aspects of self-discrepancies (actual vs ideal and actual vs ought) were stronger correlates of defeat and internal/external entrapment, and subsequently, suicidal ideation directly and indirectly compared to perfectionistic concerns. Again, defeat and internal/external entrapment acted as significant mediators in all of the conceptual models, consistent with the IMV model.
Conclusions: Overall, the studies provided robust empirical support for the central components of the IMV model by elucidating how perfectionism interacts with various cognitive-emotional vulnerabilities to elevate suicide risk. The identification of key mediators, especially defeat and entrapment, and key pre-motivational vulnerabilities, such as self-discrepancies, offers promising additional targets for clinical interventions to prevent suicide risk. This thesis advanced the theoretical understanding of the IMV model and informed future research efforts. Despite several limitations, this research provides a strong foundation for future research exploring cognitive-emotional and pre-motivational vulnerabilities to suicide risk. The integration of the Self-discrepancy Theory into the IMV model’s framework advanced the theoretical understanding of suicide risk, as well as providing robust foundations for future clinical applications and endeavours in the suicide prevention field
Electropolymerisation of hole transport materials
Get PDFThe perovskite solar cell has been the standard when it comes to organic solar cells, a steadily increasing renewable energy source which is greener than its silicon counterpart. However, even if there have been some advances such as overpassing the PCE threshold of 25% and being close to competing with silicon solar cells (PCE = 26.8% in a silicon heterojunction structure), there are still some issues in operability, more specifically the conductivity and stability, amongst others. One of the main parts of the perovskite solar cell which is proven to be causing some of the problems is the hole transport material. As well as finding new compounds which can act as competitive hole transporters, which have been proven difficult, methods of deposition of said molecules into ITO and/or FTO prior to device creation has been observed to contribute to the increase of these setbacks due to the formation of charge traps, uneven interstitial surface and poor homogeneity, amongst others. Self – assembled monolayers (molecules) (SAMs) used as hole transport materials have overcome some of these obstacles, although alternative deposition methods are still required.
This thesis describes a strategy for deposition of hole transport materials in the form of electropolymerisation. We have investigated the electropolymerisation of some hole-transporting materials and investigated the conductivity of their films
The K-theory of the C∗-algebras associated to complex dynamical systems
Get PDFWe compute the K-theory of the three C∗-algebras associated to a rational function R acting on the Riemann sphere, its Fatou set, and its Julia set. The latter C∗-algebra is a unital UCT Kirchberg algebra and is thus classified by its K-theory. The K-theory in all three cases is shown to depend only on the degree of R, the critical points of R, and the Fatou cycles of R. Our results yield new dynamical invariants for rational functions and a C∗-algebraic interpretation of the Density of Hyperbolicity Conjecture for quadratic polynomials. These calculations are possible due to new exact sequences in K-theory we induce from morphisms of C∗-correspondences
Gender-based violence in rural Scotland: complex experiences and intersecting inequalities
No full textAbstract not currently available
Examining the association between trust perceptions and suicide approval: a sociological analysis
Get PDFSociology has become a minor player in the study of suicide, with previous analyses tending to focus on how structural aspects of social relationships are implicated in suicide risk. By contrast, less attention has been given to how individuals perceive their social relationships. This PhD attempts to address this oversight by examining how perceptions of trust in key social groups are associated with suicide approval, a proxy measure for suicide risk. Drawing upon existing sociological and psychological theory, trust is conceptualised as a multidimensional construct that can have different consequences for suicide risk depending on whether it is invested in more intimate or distant relationships. These ideas are empirically tested through an analysis of data from waves 6 and 7 of the World Values Survey, covering 243281 individuals across 102 countries. Measures of trust are developed by applying exploratory factor analysis to items on trust in six different groups. Results point toward two latent dimensions of particular trust (trust in neighbours and personal acquaintances) and general trust (trust in strangers, religious outgroups and national outgroups), with family trust forming a standalone item. These three trust measures are then used to predict suicide approval as part of a Bayesian multilevel model. On average, family and particular trust are found to be negatively associated with suicide approval whereas general trust is found to be positively associated with this outcome. In turn, these associations are shown to vary in magnitude across countries, suggesting they are influenced by contextual factors. It is concluded that trust perceptions may be relevant for explaining suicide risk and could have different consequences for this outcome depending on the type of relationship in which trust is embedded
Deviant ruins: tracking the decay of modernity and (trans)humanist futurity in queer body horror
No full textAbstract not currently available
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