A Systematic Review and Narrative Analysis of the Evidence for Individual Psychodynamically Informed Psychotherapy in the Treatment of Dissociative Identity Disorder in Adults.

Dissociative Identity Disorder (DID) is a highly disabling diagnosis, characterized by the presence of two or more personality states which impacts global functioning, with a substantial risk of suicide. The International Society for the Study of Trauma and Dissociation (ISSTD) published guidelines for treating DID in 2011 that noted individual Psychodynamically Informed Psychotherapy (PDIP) was a cornerstone of treatment. This paper systematically reviews the evidence base for PDIP in the treatment of adults with DID according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Thirty-five articles were located and reviewed: seven prospective longitudinal publications, 13 case series and 15 case studies. Results suggested that PDIP has been widely deployed in DID to reported good effect with a range of treatment protocols and using multiple theoretical models. Despite the positive findings observed, the evidence base remains at the level of observational-descriptive design. Creative approaches in recent years have been developed, which add empirical weight to the use of PDIP as an effective treatment. The elevation to observational-analytic designs in the Evidence-Based Medicine hierarchy has yet to take place. Bearing in mind the challenges of research in PDIP, suggestions are offered for how the evidence base might develop.