Abstract
Background: This portfolio examines how dual diagnoses of Autism Spectrum Disorder (henceforth, autism) and Borderline Personality Disorder (BPD/EUPD) are understood,
experienced, and navigated within adult mental health services. Although autism is increasingly recognised, BPD/EUPD remains highly stigmatised. Overlapping presentations,
limited autism knowledge, diagnostic assumptions, and services organised around categorical frameworks can contribute to inconsistent care and unmet need.
Empirical Part A explores the experiences of adults diagnosed with both autism and BPD/EUPD. Using reflexive thematic analysis, it identifies how gendered assumptions,
stigma, and limited recognition of autism may contribute to diagnostic overshadowing. The findings suggest that misidentification reflects not only symptom overlap but also wider
epistemic and structural issues within mental health systems.
Empirical Part B presents a qualitative study exploring mental health professionals’ experiences of working with this population, addressing a gap in the research literature.
Using reflexive thematic analysis, findings suggest that complexity is not inherent to the individual but produced within systems shaped by risk management, diagnostic frameworks, and resource constraints. Clinicians described tensions between diagnostic categories, the impact of stigma on care, and the value of trauma-informed and formulation-led approaches in making sense of overlapping presentations.
Overall, this portfolio highlights the need to move beyond categorical interpretations towards
more relational, context‑sensitive, and neurodiversity-affirming approaches to reduce servicerelated harms and improve access to meaningful support.