Abstract
Overview: Quality of life and posttraumatic growth (PTG) represent distinct aspects of the human experience, with the former examined here in relation to food intolerance and the latter reflecting growth following trauma. This thesis explores both constructs through two separate projects: a psychometric evaluation of the 'Food Intolerance Quality of Life Questionnaire' (FIQLQ) and a systematic review and meta-analysis examining psychosocial interventions that promote PTG. Together, these studies contribute to understanding how well-being can be measured and supported across different contexts. Part one presents a psychometric evaluation of the FIQLQ, a self-report measure developed to assess quality of life among individuals managing food intolerance. The study examined the measure’s factor structure, reliability, and construct validity using exploratory factor analyses. Findings supported a clear and theoretically meaningful multidimensional structure, with strong internal consistency, reliability and validity. These results provide preliminary evidence that the FIQLQ is a reliable and valid tool for assessing the impact of food intolerance on quality of life. Part two reports a systematic review and meta-analysis investigating the effectiveness of psychosocial interventions in facilitating PTG among adults who have experienced trauma. Data were synthesised from randomised controlled trials using validated PTG measures. The pooled analysis indicated a small to moderate effect (Hedges’ g = 0.45) favouring psychosocial interventions, suggesting they can enhance PTG. However, substantial heterogeneity and limited follow-up data highlight variability in effects and the need for further longitudinal research.
Together, these studies advance understanding of how individuals adapt and sustain well-being, providing a validated measure of quality of life and evidence for psychosocial approaches that promote growth following trauma.