ReviewA Review of Dissociative Disorders Treatment StudiesBrand, Bethany L. PhD*; Classen, Catherine C. PhD†; McNary, Scot W. PhD‡; Zaveri, Parin PhD§ Author Information *Department of Psychology, Towson University, Towson, MD; †Women's Mental Health Research Program, at the Women's College Research Institute, Women’s College Hospital and Department of Psychiatry, University of Toronto, Toronto, ON, Canada; ‡Department of Educational Technology and Literacy, Towson University, Towson, MD; and §Washington DC Veterans Affairs Medical Center, Trauma Disorders Program at Sheppard Pratt Health Systems, Baltimore, MD. Send reprint requests to Bethany Brand, PhD, Department of Psychology, Towson University, 8000 York Rd, Towson, MD 21252–0001. E-mail: [email protected]. The Brand et al. study (2009) was not included in the analyses because follow-up data was no available when this review was conducted. The Journal of Nervous and Mental Disease: September 2009 - Volume 197 - Issue 9 - p 646-654 doi: 10.1097/NMD.0b013e3181b3afaa Buy Metrics Abstract This review examines empirical reports of treatment for Dissociative Disorders (DD), including 16 DD treatment outcome studies and 4 case studies that used standardized measures. Collectively, these reports suggest that treatment for DD is associated with decreased symptoms of dissociation, depression, posttraumatic stress disorder, distress, and suicidality. Effect sizes, based on pre/post measures, are in the medium to large range across studies. Patients with dissociative disorder who integrated their dissociated self states were found to have reduced symptomatology compared with those who did not integrate. The magnitude of pre/post effect sizes for these DD studies are comparable to pre/post effect sizes in treatment studies of complex PTSD. There are significant methodological limitations in the current DD treatment outcome literature that reduce internal and external validity including regression towards the mean, limited sample sizes, and nonrandomized research designs. Implications for future research and treatment planning for patients suffering from DD are discussed. © 2009 Lippincott Williams & Wilkins, Inc.