Empirical Testing of Criteria for Dissociative Schizophrenia

Abstract

This study examined the validity of dissociative schizophrenia diagnostic criteria. In the first phase, 50 participants with a psychotic disorder were administered the Dissociative Experiences Scale and the Childhood Trauma Questionnaire to identify those with dissociative characteristics. In the second phase, we selected those who had a score of 15 or above on the Dissociative Experiences Scale. Fifteen of these participants were evaluated thoroughly with the Structured Clinical Interview for DSM–IV Axis I, Structured Clinical Interview for DSM–IV Axis II, and Structured Clinical Interview for DSM–IV Dissociative Disorders to determine whether they met the criteria for dissociative schizophrenia and to generate a clinical description. Our results indicated that 24% of the individuals we tested met these criteria. We propose making mandatory 1 of the 3 dissociative symptoms of the criteria to eliminate people with only nonspecific symptoms (e.g., extensive comorbidity). According to this modified criterion, 14% of our sample would receive a diagnosis of dissociative schizophrenia. However, a more comprehensive look at the clinical picture begs the question of whether dissociative schizophrenia is truly present in every person meeting the criteria. We discuss the relevance of creating a new schizophrenia subtype and offer recommendations for clinicians.

Keywords:

• dissociation
• schizophrenia
• dissociative disorders
• diagnostic validity

Acknowledgments

The authors would like to thank the individuals who agreed to participate in this study; Dr. Pierre Lalonde, Dr. Constantin Tranulis, Dr. Marie Villeneuve, and other Hôpital Louis-H. Lafontaine professionals who participated in the recruitment; as well as Ann-Marie Lambert, MPs, for her valuable review before submission. The first author benefited from a graduate training award from the Canadian Institutes of Health Research.