Multiscale Dissociation Inventory (MDI)
Note: This measure currently cannot be purchased from Psychological Assessment Resources (PAR). However, PAR has decided to offer and support the MDI again in the coming months. Stay tuned!
Until redistributed by PAR, the MDI is available at no charge to qualified professional researchers, or thesis/dissertation students supervised by a licensed psychologist. For those who meet this condition, and wish to received the MDI test packet, please email John Briere with a request.
The MDI is a 30-item self-report test of dissociative symptomatology. It is fully standardized and normed, and measures six different type of dissociative response. The scales of the MDI (with their associated alpha reliabilities in the general population) are:
- Disengagement (alpha = .83)
- Depersonalization (alpha = .90)
- Derealization (alpha = .91)
- Emotional Constriction/Numbing (alpha = .94)
- Memory Disturbance (alpha = .74)
- Identity Dissociation (alpha = .75)
- Total Dissociation Score (alpha = .96)
The MDI is normed and standardized on 444 trauma-exposed individuals from the general population, and validated in clinical, community, and university samples. Scores on this measure can be converted to T-scores that allow for empirically-based clinical interpretation of clients’ actual level of dissociative disturbance.
The MDI has been found to have good psychometric qualities in both the normative and validation samples. Data on over 1,300 clinical and nonclinical individuals indicates that the MDI does, in fact, tap relatively independent types of dissociative responses that correlate, as expected, with the MDI scales (Briere, Weathers, & Runtz, 2005). A raw Identity Dissociation scale score of 15 or higher was found to identify 93% of those with diagnosis of Dissociative Identity Disorder (DID) and 92% of those with no diagnosis of DID in a combined clinical/community sample. Each MDI symptom item is rated according to its frequency of occurrence over the prior month, using a scale ranging from 1 (never) to 5 (very often).
The MDI requires approximately 10-15 minutes to complete for all but the most clinically impaired individuals and usually can be scored and profiled in less than 5 minutes.