Assessing dissociation: A systematic review and evaluation of existing measures.

Objective: This review aimed to assess the psychometric properties and methodological quality of existing dissociation measures.

Methods: MEDLINE, Embase, and PsycINFO were searched in May 2023 using comprehensive search terms for 'dissociation' combined with terms for 'measurement' and 'psychometric properties'. The review was registered with PROSPERO (CRD42023423485) and followed PRISMA and COSMIN guidelines. We assessed content validity, structural validity, cross-cultural validity, and different indices of reliability comprising 1) reliability (test-retest, inter-rater, intra-rater), 2) internal consistency, and 3) measurement error.

Results: Of 7570 studies, 170 were eligible, revealing 44 measures of dissociation (86% trait dissociation, 14% state dissociation) and their 14 adapted versions. None of the measures met all COSMIN criteria for good psychometric properties and high methodological quality. Overall, methodological quality was rated as follows: 'doubtful' for content validity, 'adequate' for measurement error and cross-cultural validity, and 'very good' for structural validity and internal consistency. Most included studies did not assess the reliability of investigated measures.

Conclusions: The Dissociative Experiences Scale (DES), adolescent DES, Peritraumatic Dissociative Experiences Questionnaire, Somatoform Dissociation Questionnaire-20, and Cambridge Depersonalisation Scale demonstrated strong evidence for measuring general, child/adolescent, trauma-related (state) or somatoform dissociation, and depersonalisation, respectively. Future research should refine or develop dissociation measures following COSMIN guidelines to ensure robust methodology and psychometric properties.