A critical review of dissociative trance and possession disorders: Etiological, diagnostic, therapeutic, and nosological issues

Objective: Although the Diagnostic and Statistical Manual of Mental Disorders (DSM), Fourth Edition, acknowledges the existence of dissociative trance and possession disorders, simply named dissociative trance disorder (DTD), it asks for further studies to assess its clinical utility in the DSM-5. To answer this question, we conducted the first review of the medical literature. Method: The MEDLINE, CINAHL, and PsycINFO databases were searched from 1988 to 2010, seeking case reports of DTD according to the DSM or the International Classification of Diseases definitions. For each article, we collected epidemiologic and clinical data, explanatory models used by authors, treatments, and information on the outcome. Results: We found 28 articles reporting 402 cases of patients with DTD worldwide. The data show an equal proportion of female and male patients, and a predominance of possession (69%), compared with trance (31%). Amnesia is reported by 20% of patients. Conversely, hallucinatory symptoms during possession episodes were found in 56% of patients and thus should feature as an important criterion. Somatic complaints are found in 34% of patients. Multiple explanatory models are simultaneously held and appear to be complementary. Conclusion: Data strongly suggest the inclusion of DTD in the DSM-5, provided certain adjustments are implemented. DTD is a widespread disorder that can be understood as a global idiom of distress, probably underdiagnosed in Western countries owing to cultural biases, whose incidence could increase given the rising flow of migration. Accurate diagnosis and appropriate management should result from a comprehensive evaluation both of sociocultural and of idiosyncratic issues, among which acculturation difficulties should systematically be considered, especially in cross-cultural settings.