The Multidimensional Inventory of Dissociation (MID) in Depersonalization Disorder: General Findings with a Clinical Emphasis on Memory and Identity Disturbances

The Multidimensional Inventory of Dissociation (MID) was administered to 23 participants diagnosed with DSM-IV-TR Depersonalization Disorder (DDD) by structured interview. The MID has not been previously examined in DDD and does not generate a diagnostic formula for the disorder. Mean MID score for the sample was modestly elevated at 18.54, and was significantly correlated with Dissociative Experiences Scale, Cambridge Depersonalization Scale, and Childhood Trauma Questionnaire scores. Criterion A (General Dissociation) Depersonalization and Depersonalization scale scores were markedly elevated (41.70 and 40.98 respectively), followed by moderate elevations in the Identity Confusion (36.01), Trance (25.44), and Memory Problems (23.30) scales. Criterion B (Intrusions from partly dissociated self-states) mean score was modestly elevated (19.13) and declined to 13.67 once items overlapping with the Depersonalization and Identity Confusion scales were excluded. Criterion C (fully dissociated manifestations of other self-states) mean score was minimally elevated (6.57). Of the 168 pathological dissociation items, 55 were clinically elevated in DDD. Closer examination of the Intrusions and Amnesia items that were modestly elevated in DDD revealed that these items did not reflect the presence of alters, but rather represented known depersonalization-related phenomena. We propose a preliminary formula, based on cutoff scores for Criterion A Depersonalization and/or Derealization, Criterion B, and Criterion C (≥20, ≤28, ≤11) for the sensitive diagnosis of DDD (82.6% of participants), which would require future investigation for replication and determination of specificity vis-à-vis the other dissociative disorders.