Abstract
Self-disgust, defined as the dysfunctional self-focused internalisation of the otherwise adaptive disgust response, is characterised by intense and persistent feelings of repulsion towards oneself. Unlike other self-conscious emotions, self-disgust remains less explored in psychological research despite its transdiagnostic nature and likely role in the onset and progression of various mental health problems. One such problem is suicidal ideation, a significant public health issue among New Zealand youth. The current thesis sought to elucidate the trajectory from self-disgust to suicidal ideation using three extant theories of suicide (the interpersonal theory, the integrated motivational-volitional model, and the three-step theory)—a connection that has not been previously investigated in published literature.
The primary aim of this thesis was to identify which theoretical framework most robustly explains the relationship between self-disgust and suicidal ideation. Additional aims included identifying key predictors of self-disgust, investigating the potential buffering role of self-compassion within the proposed pathways, and exploring cross-cultural differences in self-disgust expression between Māori and non-Māori participants.
It was hypothesised that the IMV and 3ST frameworks would demonstrate stronger and statistically significant relationships between self-disgust and suicidal ideation compared to the ITS, due to reduced construct overlap. It was further expected that all proposed drivers (e.g., adverse childhood experiences) would significantly predict higher levels of self-disgust, and that self-compassion would attenuate the mediated relationships between self-disgust and suicidal ideation. Finally, it was predicted that cultural differences would emerge, with Māori and non-Māori participants showing differences in self-disgust scores, reflecting culturally specific influences on self-disgust expression.
This thesis included a cross-sectional pilot study (n = 106) examining the proposed relationship between self-disgust and interpersonal needs, and a three-wave prospective study (n = 240) that included suicidal ideation and explored additional suicide theories. Undergraduate psychology students completed questionnaires assessing relevant constructs across both studies. The measures assessed self-disgust, suicidal ideation, self-compassion, predictors of self-disgust, proposed mechanisms underlying suicidal thinking, and covariates (i.e., shame and self-hate). Regression analyses tested hypotheses in the pilot study, while dynamic panel modelling was employed in the prospective study.
The findings did not support the hypothesised trajectories, indicating that the proposed suicide frameworks may not adequately explain the relationship between self-disgust and suicidal ideation. Cross-cultural analyses also revealed no significant differences in self-disgust experiences between Māori and non-Māori participants, contrary to expectations of cultural variability. Among the hypothesised drivers, sexual abuse emerged as the key predictor of self-disgust, while other proposed predictors received little empirical support. Furthermore, self-compassion did not significantly diminish the relationship between self-disgust and suicidal ideation, challenging theoretical assumptions and empirical findings.
The lack of support for most hypotheses may stem from limitations in sample characteristics, methodology, and the measurement of self-disgust. Future research should focus on addressing methodological issues, improving the precision and cultural validity of self-disgust measurement, and exploring alternative theoretical frameworks that may better capture the complexity of self-disgust and its role towards suicidal ideation. Addressing these limitations and expanding on the research could yield valuable insights and inform the development of more effective, targeted interventions.