Exploring the Relationship Between Complex Trauma, Complex Posttraumatic Stress Symptomology and Non-suicidal Self-injury: A Mixed-method Investigation

Abstract

Background: Previous research has emphasised the role of childhood trauma, particularly interpersonal trauma, in predisposing individuals to developing Complex Posttraumatic Stress Disorder (C-PTSD) and Non-Suicidal Self-injury (NSSI). C-PTSD is a condition that arises from prolonged exposure to trauma. Previous literature indicates that people with C-PTSD are at increased risk of engaging in NSSI. Despite this association, there is a paucity of research that explored how complex trauma and the subsequent development of C-PTSD would influence NSSI and how these experiences interact over time. Aims: To better understand the intricate relationships between complex trauma, C-PTSD and NSSI, shedding light on the underlying factors and potential impacts. Through exploring personal narratives, the thesis also aimed to provide valuable insight into the complex nature of NSSI within the context of C-PTSD. Method: Study 1 involved a secondary data analysis study using a subsample (n=2,480) from a national household survey to explore the relationship between PTSD symptom clusters (i.e., intrusion and arousal), childhood interpersonal trauma (CIT), perceived social support and lifetime NSSI. Study 2 is a systematic review that narratively synthesised the quantitative evidence regarding the mediating role of C-PTSD-related difficulties in the association between CIT and NSSI. Study 3 involved a qualitative investigation of the lived experience of eight individuals aged 20-56 years. Using a novel narrative approach, the study aimed at explore the individuals’ accounts of how complex trauma and subsequent development of C-PTSD have contributed to NSSI and the factors that have helped them to manage their NSSI. Results: The series of logistic regression analyses in Study 1 revealed that the PTSD arousal symptom cluster was a stronger predictor of lifetime NSSI compared to the intrusion symptom cluster. CIT and perceived social support were not statistically significant moderators in this association. The systematic review (Study 2) identified 704 studies but only 27 of these studies were eligible to include. The overall findings support the role of C-PTSD difficulties (i.e., PTSD, emotion dysregulation, negative self-concept, and related constructs) as significant mediators in the relationship between CIT and NSSI. Across several emotion dysregulation dimensions, limited access to emotion regulation strategies appeared to be the strongest mediator. Results from thematic narrative analysis (Study 3) support the role of early complex trauma and C-PTSD on NSSI and suggest a complex relationship among these experiences that evolve over time. Four primary themes were established, namely, 1) the dysfunctional system, “shaky foundations” leading to future traumas, 2) the link between complex trauma, mental health difficulties, and NSSI, and 3) the role of autonomy and sense of control in managing NSSI. Conclusion: The overall findings support the role of early exposure to complex trauma in increasing the vulnerability to developing C-PTSD-related difficulties and NSSI and suggest complex dynamic relationships between these experiences. The findings highlight the importance of designing interventions that address the specific needs of individuals with C-PTSD and NSSI. Empowering individuals to improve their control and autonomy should be considered when designing treatment plans. As individuals' mental health difficulties are changing and evolving, flexible and person-centred treatment should be adapted to fulfil the complex needs of these individuals.