Abstract
BACKGROUND: Parity of Esteem (PoE) is about equality between mental and physical health but is a term lacking definition and clarity. The complexity of the field of mental health and the conversations around PoE add to its opacity. Therefore, the aim of this study is to use systems thinking to explore the strengths and challenges of using PoE. METHODS: This is a secondary analysis of descriptive qualitative data, from 27 qualitative interviews, utilising the World Health Organisation (WHO) system domains as a framework for the inductive thematic analysis. RESULTS: Examining the current strengths and challenges of systems in mental and physical healthcare using the WHO domains and macro, meso and micro levels, identifies specific actions to redress inequity between mental and physical health provision. CONCLUSION: The evidence suggests that moving PoE from rhetoric towards reality requires new configurations with a systems orientation, which uses macro, meso and micro levels to analyse and understand the complexity of relations within and between domain levels and reorienting funding, training and measurement. This requires embedding new competencies, infrastructures and practices within an effective learning healthcare system.