A call for standardization: A case study of theoretical ambiguity in mental illness labeling and stigma research via...

Despite more than 60 years of research, the specific effects of mental illness/psychiatric labels on stigma remain unclear. As pointed out in prior systematic reviews, one reason for this ambiguity is that researchers conceptualize key variables differently. Since conceptualization is derived from theory, we conducted a pre-registered systematic review to investigate the definition and operationalization of mental illness stigma. On one hand, we find that fewer than half of the reviewed studies define stigma, and among those that do, definitions vary-even when citing the same foundational sources. On the other hand, there is an increasing use of social distance as a measure of stigma-a trend which suggests the beginnings of methodological consensus. We hope these convergences will inspire theoretical consensus and methodological cohesion, particularly if paired with more rigorous attention to how social distance is defined and measured. Such theoretical consensus would allow knowledge to accumulate, paving the way for the development of more effective evidence-based interventions to reduce mental illness stigma.