The OMSEDD was originally developed to assist psychiatric residents with assessment of complex dissociative and posttraumatic psychopathologies. Accordingly, it uses a phenomological approach to symptom clusters that commonly appear in patients with dissociative disorders and complex PTSD. This system was designed at a time when diagnosis of dissociative identity disorder (then multiple personality disorder) was primarily based in attempts to elicit alter self states, often by using hypnosis or similar intrusive methods. This was problematic since many clinicians were/are not trained in hypnosis and/or comfortable with using this method for diagnosis. At that time, experts frequently voiced concerns about the production of hypnotic artifacts that could be misidentified as alters, particularly in those inexperienced with either DID or hypnosis or both. The OMSEDD allowed the clinician to explore 6 symptom clusters: dissociative process symptoms, amnesia, auto-hypnotic symptoms, PTSD symptoms, somatoform symptoms, and mood symptoms. Frequently, in DID patients, assessment of these clusters allowed the direct emergence of alter identities, without intrusive methods, during the interview. This interview does not replace structured screening and diagnostic inventories for DID. However, it allows assessment of complex dissociative symptoms in any clinical interview in any clinical setting.

In addition to discussion of diagnosis and differential diagnosis of dissociative disorders using the OMSEDD, this presentation will include clinical examples from a video of a DID patient being interviewed.