Cognitive behavioural therapy is not universally evidence-based: implications for eating disorders.

Cognitive behavioural therapy (CBT) is widely described as an evidence-based psychological treatment, including within eating disorder (ED) care. However, evidence claims are only valid within the boundaries of the populations, outcome measures, and service contexts represented in the underlying trials. This paper argues that CBT is not universally evidence-based and that extending its evidentiary status to neurodivergent people and Indigenous, First Nations, and Māori communities is not currently justified. Drawing on decolonial and neurodiversity scholarship and lived experience-led literature, the paper shows how research designs prioritising internal validity have contributed to an evidence base that functions as a methodological echo chamber, reproducing findings drawn predominantly from white, Western, largely neurotypical samples. As a result, CBT trials often lack external validity for communities whose experiences of distress are shaped by sensory processing differences, executive functioning difficulties, systemic discrimination, food insecurity, and the colonial legacy of trauma, erasure, and dispossession. In ED care, these limitations are amplified by diagnostic frameworks and outcome measures that privilege weight-centric approaches and neuronormative and Eurocentric cognitive models while overlooking sensory, somatic, cultural, and socio-political drivers of illness. Evidence from autistic and Indigenous participants documents mis-attunement and iatrogenic harm within standard CBT-based pathways for EDs. The paper concludes that universal claims about CBT are not supported by the current evidence base and are better understood as population-specific evidence claims grounded in co-designed trials, culturally valid measurement, and implementation research demonstrating safety, relevance, and benefit for diverse communities.