Research examining the aetiology of suicide suggests that suicidal thoughts and
behaviours arise out of the interaction between a range of risk and protective variables. As a result, individual risk factors are limited in predictability of suicide. Emerging developments in the field of suicide have thus focussed on theoretical models that aim to explain the development of suicidal thoughts and behaviours. The Integrated Motivational-Volitional model (IMV) of suicide is a tri-partite model outlining the development of suicidal thoughts and behaviour. This model proposes that specific background factors within the premotivational phase increase the vulnerability to feelings of defeat; individuals feeling
defeated can feel trapped within these feelings (internal entrapment) or situation (external entrapment); and that individuals feeling trapped may view suicide as a means of escape.
Adverse childhood experiences (ACEs) have been associated with a dose-response risk of suicide. From the perspective of the IMV model, ACEs are presented as premotivational phase variables that increase vulnerability to defeat. However, it is unclear why
experiencing increased adversity in childhood could result in increased feelings of defeat. As a result, the current thesis draws from the dimensional model of adversity and
psychopathology (DMAP) to address this gap and investigate the pathways by which ACEs are likely to affect feelings of defeat. Specifically, the DMAP proposes that different dimensions of adversity (i.e., threat and deprivation) affect development through distinct pathways. Consistent with this, threatening experiences in childhood are expected to impact emotional processing while deprivation is expected to impact executive functioning and
language abilities. The overarching aim of the current thesis is thus to draw from the IMV model and the DMAP to investigate the pathways by which ACEs affect suicidal thoughts.
This aim was addressed through a systematic review and 3 empirical studies among adults in
the UK. Firstly, a systematic review (Chapter 3) of 98 records (100 studies) testing the IMV
model was conducted to examine the empirical support for the overall model and establish
the role of ACEs from the perspective of the model. The findings indicated that the defeatentrapment-
suicidal ideation pathway was supported. However, there was limited research on
the role of ACEs as a pre-motivational phase variable within the IMV model. Study 2
(Chapter 4) used secondary data from 502 participants to investigate whether
defeat/entrapment mediated the relationship between ACEs and suicidal ideation. While defeat, internal entrapment, and external entrapment were initially hypothesised to be distinct,
confirmatory factor analyses indicated very high covariances between these variables in the short defeat and entrapment scale and they were conceptualised as a single variable in this study. The findings indicated that defeat/entrapment mediated the relationship between ACEs and suicidal ideation.
Drawing from the DMAP, study 3 (Chapter 5) collected data from 251 adults in the UK recruited from Prolific Academic to investigate whether emotional processing, executive functioning, and language abilities mediate the relationship between ACEs (conceptualised as threat/deprivation) and defeat. The findings indicated that individuals with a history of
physical violence (threat) are more likely to experience higher defeat through expressive suppression while individuals with a history of cognitive neglect (deprivation) were more likely to experience higher defeat due to heightened emotional reactivity, expressive suppression, and language difficulties. Finally, study 4 (Chapter 6) investigated whether
positive childhood experiences buffered the pathways between adversities involving threat and deprivation in childhood and developmental factors (emotional processing, executive functioning, and language abilities) and the pathways between these developmental factors
and defeat using multigroup analyses. The findings indicated that physical violence was significantly associated with expressive suppression in the low PCEs group but not the high
PCEs group. Similarly, supervision neglect was associated with attention/concentration
difficulties in the low PCEs group alone. In contrast, sexual abuse was linked with language and verbal memory difficulties in the high PCEs group but not the low PCEs group.
However, none of these group differences were statistically significant suggesting that PCEs may not moderate the pathways between threat/deprivation and developmental outcomes
through these developmental factors. In contrast, likelihood ratio tests indicated that the effect of language abilities and verbal memory to defeat as well as direct effects of sexual abuse and
cognitive neglect on defeat were moderated by PCEs. These findings may be limited by low sample size in each PCE group and thus require further investigation.
Taken together, the investigations presented in this thesis thus outline novel pathways that may explain the link between ACEs and suicidal thoughts and protective factors that may
influence these relationships. Upon replication in prospective analyses, these findings regarding developmental mediators and the role of defeat and internal entrapment have implications for clinical practice and the development of interventions. Additionally, while these findings are exploratory, these have the potential to inform policy and practice
| Date of Award | 22 Nov 2024 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | University of Strathclyde |
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| Supervisor | Susan Rasmussen (Supervisor) & Edward Sosu (Supervisor) |
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