The conceptualization and assessment of dissociation: An umbrella review of synthesis studies

: Dissociation is a central yet controversial topic in psychopathology, eliciting interest from diverse areas of mental health research and clinical practice. Fundamental debates persist regarding its conceptualization and measurement. The present umbrella review synthesizes findings from all existing systematic reviews (n = 44), meta-analyses (n = 27), and mixed works (i.e., both systematic reviews and meta-analyses; n = 4) on dissociation, published between 1996 and 2025, encompassing 3864 primary studies and over 1,596,432 participants. We addressed three foundational questions: (1) Is dissociation conceptualized and measured as a categorical or dimensional construct? (2) Is it conceptualized and measured as unidimensional or multidimensional? (3) Do synthesis studies account for sample-specific factors such as culture, language, or environment? Regarding (1), findings revealed an almost equal split in the conceptualization of dissociation as categorical versus dimensional. However, measurement predominantly employs continuous scales, revealing inconsistencies between theoretical framing and empirical methods. Regarding (2), most studies endorse a multidimensional understanding of dissociation. Yet, most studies rely on total scores rather than subscale-level analyses. This suggests divergence in how multidimensionality is operationalized. Regarding (3), despite frequent use of group comparisons, few reviews systematically address cross-cultural or contextual comparability. This raises concerns about measurement validity across diverse populations. Overall, this review highlights a hybrid and sometimes inconsistent approach to dissociation in the literature. Advancing the field requires greater alignment between conceptual models and methods of operationalization, as well as systematic attention to cultural and contextual influences on dissociation assessment. Establishing consensus in these areas will strengthen theoretical clarity and improve the rigor and relevance of future research on dissociation.