The Stanford Dissociation Questionnaire: A Three-Facet Measure of Trait and State Dissociation

Dissociation is a widespread phenomenon with profound implications for mental health. To date, researchers have relied upon broad conceptualizations and retrospective measures, making it difficult to identify a consistent subset of experiences, explore their links to related phenomena, and differentiate habitual from momentary dissociation. To address these issues, we introduce the Stanford Dissociation Questionnaire (SDQ), a 9-item measure that assesses three facets of dissociation and can be employed to assess either trait or state dissociation. Using the SDQ, we seek to clarify the structure and correlates of dissociation. Across three studies (N_total = 976), we demonstrate that trait and state versions of the SDQ exhibit strong content validity and a theoretically congruent factor structure, comprised of alteration in the perception of one’s mind, body, and world (suggesting a tripartite model of dissociation). This structure was largely invariant across demographic groups and time. We also demonstrate good convergent and discriminant validity, internal consistency, and temporal stability over one week. Overall, we conclude that the trait and state versions of the SDQ are reliable and valid tools that can enhance our understanding of dissociation's structure, antecedents, and consequences.