Validation of the Multidimensional Inventory of Dissociation-60 (MID-60) Items in a Clinical Population

The Multidimensional Inventory of Dissociation-60 (MID-60) was validated in adults in clinical care using data from 13,177 de-identified assessments on an Australian online psychometric platform. Analyses used subsamples defined by available measures for factor, reliability, and validity testing. Confirmatory factor analysis supported the intended 11-factor structure, with good conventional fit and acceptable robust fit after correction for non-normality. Internal consistency (α = .98) and short-interval test-retest reliability were high. The MID-60 converged strongly with the Dissociative Experiences Scale II (DES-II; r = .80) yet was able to identify milder clinical presentations that the DES-II cut-off often misses. Convergence with the International Trauma Questionnaire (r = .64) and graded associations with the World Health Organization Disability Assessment Schedule 2.0 (r = .50) supported links to trauma symptoms and disability. MID-60 scores decreased over repeated administrations of 2 to 12 months. Findings confirm the MID-60 as a reliable, valid, and clinically sensitive measure for screening, formulation, and progress monitoring.