Relations among peritraumatic dissociation and posttraumatic stress: a meta-analysis.

A meta-analysis was performed on the empirical literature which addressed the relationship of peritraumatic dissociation to posttraumatic stress (PTS). Extensive literature searches were conducted to identify as many relevant studies as possible, and revealed 59 independent eligible studies. All studies were coded using a detailed code sheet that included effect measures, variables that indicated the methodological quality of the studies, and substantial variables that might theoretically affect the relationship between peritraumatic dissociation and PTS. A significant positive relation between peritraumatic dissociation and PTS was found. Differences in the methodological rigor between studies - time elapsed since peritraumatic dissociation, design, sample type, and study type - significantly and sufficiently explained the variability in effect sizes between studies. Theoretical variables did not explain such variability. Although results underline earlier findings, due to designs of the reviewed studies no conclusions could be drawn as to causal relations between peritraumatic dissociation and PTS.