Elucidating the Construct of Dissociation through Scale Development

The ultimate goal of this study was to create a comprehensive and psychometrically sound measure of dissociation and, in the process, to elucidate the boundaries of the nomological net of dissociation. An item pool of 593 items organized into 39 Homogeneous Item Composites (HICs) was created based on a comprehensive review of the literature, with the goal of thoroughly sampling all constructs labeled as dissociation across research and clinical areas. After expert review and discussion, several HICs were collapsed due to high content overlap, resulting in an item pool of 195 items organized into 14 HICs before data collection. The study consisted of three phases. The first phase was a pilot study with a student sample that resulted in discarding 12 items due to iter-item correlations of .80 and above. The second phase used a large sample containing subsamples of patients (N = 392) and community members (N = 407), who were recruited from Amazon Mechanical Turk. This phase established robust, factor analytically derived scales and facets that replicated across subsamples, resulting in the creation of the Measure of Dissociative Experiences (MODE), which contains 105 items that constitute three scales with a total of nine facets. The three scales are Reality Detachment (with facets Psychotic Dissociation and Neurological Dissociation), Numbing Detachment (with facets Dissociative Stress Reaction, Depersonalization, Emotional Numbing, and Weak Sense of Self), and Absorption (with facets Flashbacks, Fantasy Proneness, and Hyperfocus). This phase also established preliminary convergent and discriminant validity. The third phase used a high-risk community sample and a student re-test sample to attempt to replicate and extend the findings of phase two, by examining convergent and discriminant validity. Overall, the MODE showed good structural validity as evidenced by a robust and stable structure, good content validity as evidenced by the item pool comprehensively including all potential constructs of dissociation, and good convergent and discriminant validity.