Is dissociation a multidimensional construct? Data from the Multiscale Dissociation Inventory.

The dimensionality of dissociation was examined in a combined sample of 1,326 general population, clinical, and university participants who completed the Multiscale Dissociation Inventory (MDI). Principal components analysis identified five moderately intercorrelated factors (mean r = .39): Disengagement, Identity Dissociation, Emotional Constriction, Memory Disturbance, and Depersonalization/Derealization. Differential relationships were found between individual MDI factors and demographics, trauma history, clinical status, posttraumatic stress, and scores on other dissociation measures. Surprisingly, after controlling for sex and age, trauma exposure accounted for only 3 to 7% of the variance in MDI factors. The notion of dissociation as a general trait was not supported. Instead, dissociation may represent a variety of phenomenologically distinct and only moderately related symptom clusters whose ultimate commonality is more theoretical than empirical.