Dissociation, self-states and social anxiety: relationships and measurement

Abstract

Dissociation is increasingly recognised as a transdiagnostic process with significant implications for psychological functioning and treatment outcomes. Difficulties in emotional regulation, social functioning, and therapeutic outcomes are associated with dissociative processes across a range of mental health presentations. Despite its relevance, dissociation remains poorly differentiated in much of the empirical literature, with a reliance on broad measures that offer limited insight into specific mechanisms, such as disruptions between self-states. This thesis contributes to a more refined understanding of dissociation through two complementary studies.The first line of enquiry explored the relationship between dissociation and social anxiety, a condition characterised by disrupted self and social processing, where emerging evidence suggests dissociative experiences may be particularly relevant. A systematic review identified 17 quantitative studies that measured both dissociation and social anxiety, with a meta-analysis conducted on a subset of 11 studies, indicating a moderate positive association (r = .39) between the two constructs. The review also highlighted potential moderating and mediating factors including childhood trauma and emotion regulation difficulties.Building on these findings, the second study sought to evaluate the psychometric properties of the Dissociation-Integration of Self-States Scale (D-ISS), a theory-driven measure of dissociation between self-states, grounded in a cognitive model of dissociation. This validation study included 344 clinical participants and 147 non-clinical participants, enabling comparison between groups. Results supported the internal consistency, test-retest reliability, convergent validity, partial divergentvalidity, and five-factor structure of the D-ISS. The scale differentiated between clinical and non-clinical groups, providing evidence for its potential clinical utility in assessing dissociation between self-states. Both studies, built on insights from empirical and quantitative research, contribute to improving the conceptualisation and measurement of dissociation in clinical contexts. In particular, they highlight the importance of recognising and assessing dissociation across a range of mental health presentations, beyond its traditional associations with dissociative disorders and post-traumatic stress disorder. These findings have important implications for clinical assessment practices, highlighting the value of measuring specific dissociative processes, such as self-state fragmentation. Incorporating dissociation-focused measures should help to enhance case formulation and guide more targeted and effective interventions. Finally, the studies offer directions for future research, including the importance of assessing, formulating and intervening with dissociation in the context of social anxiety, and the continued development of robust measures of specific forms of dissociation