Exploring the co-occurrence of self-harm and aggression from multiple layers: a multi-method investigation of dual harm

Abstract

Historically, research and practice have separated between self-harm and aggression. However, there is growing evidence that these behaviours may be linked, share common risk factors and co-occur. The co-occurrence of self-harm and aggression has been termed dual harm. Given the lack of research in the area of dual harm, there is limited understanding of this phenomenon and why individuals may engage in this behaviour. Therefore, this thesis aimed to address the gaps in the literature by extending understanding of dual harm and how this construct may be best conceptualised within research and practice. A multi-method approach was adopted to achieve the above aim, including a narrative review (Chapter 3), systematic review (Chapter 4), secondary data analysis (Chapter 5), cross-sectional and longitudinal study (Chapter 6), and qualitative study (Chapter 7). First, Chapter 1 provides an introduction to the topic of area, specifying the gaps in the literature and how these will be addressed. Following this, Chapter 2 provides a discussion of the methodology utilised by the studies within this thesis. Based on a narrative review of the literature, Chapter 3 presents the first holistic theory of dual harm – the cognitive emotional model of dual harm. Subsequently, Chapter 4 provides a systematic review, with findings suggesting that dual harm would be best understood as an overlap between self-harm and aggression and their risk factors. Chapter 5 presents a secondary data analysis of the Avon Longitudinal Study of Parents and Children, providing exploratory evidence that relational forms of aggression should not be included in definitions of dual harm. Chapter 6 reports findings of a questionnaire-based study involving 43 forensic mental health service users. Results demonstrated that emotional dysregulation is significantly positively associated with dual harm behaviour and ideation at a baseline assessment and again at one-month follow-up. Dual harm ideation was also found to be significantly positively associated with dual harm behaviour at baseline. Moreover, secondary psychopathy was significantly positively linked to dual harm ideation at baseline and follow-up. Finally, emotional dysregulation was a mediator in the relationship between secondary psychopathy and dual harm ideation and behaviour at baseline and follow-up. Chapter 7 presents a qualitative interview study with 16 forensic mental health service users. Participants highlighted the duality of their self-harm and aggression, reporting that these behaviours were primarily used to serve the function of emotional regulation. These individuals also highlighted a range of risk factors associated with their dual harm, including emotional dysregulation, perceived lack of social support and contextual factors. Finally, chapter 8 triangulates the findings presented within this thesis and discussed these in the context of the wider literature. Implications for practice and future research are outlined. By investigating dual harm from multiple angles, this thesis sheds light on various aspects of dual harm, thereby providing important and original contributions to this field. This work provide the following clinical implications: 1) consideration of the duality of self-harm and aggression, 2) transdiagnostic approaches that target the shared risk factors of self-harm and aggression, 3) focus on the functionality of dual harm, and 4) prioritisation of recovery-orientated practice. Future research should build upon this thesis to provide a more robust understanding of dual harm by following the recommendations suggested by the author.

Date of Award	1 Aug 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Daniel Pratt (Supervisor) & Peter Taylor (Supervisor)