Prevalence of dissociative disorders in psychiatric in-patients: the impact of study characteristics

Objective: Prevalence rates for dissociative disorders among psychiatric in -patients vary widely. The aim of this meta-analysis is to offer an explana tion for these differences. Method: Prevalence studies using a clinical diagnostic interview among psyc hiatric in-patients were included. Hypotheses concerning the impact of blin d versus not blind designs, choice of diagnostic instrument and continental background were tested. Results: Nine studies met the inclusion criteria. In blind studies the prev alence rate for dissociative disorders was significantly lower (but not for DID). Studies using the SCID-D (compared to the DDIS) and European studies had significantly lower prevalence rates for both dissociative disorders a s well as for DID. Conclusion: The choice of diagnostic instrument and cultural differences in interpretation of symptoms are major explanations for differences in preva lence of dissociative disorders and DID. Comparative, blind research using both DDIS and SCID-D in the assessment of dissociative disorders is advised .