The Relationship Between Dissociation and Symptoms of Psychosis: A Meta-analysis.

Evidence suggests that dissociation is associated with psychotic experiences, particularly hallucinations, but also other symptoms. However, until now, symptom-specific relationships with dissociation have not been comprehensively synthesized. This is the first prospectively registered (CRD42017058214) meta-analysis to quantify the magnitude of association between dissociative experiences and all symptoms of psychosis. MEDLINE, PsycINFO, PubMed, and Scopus databases were searched using exhaustive terms denoting dissociation and psychotic symptoms. We included both nonclinical (58 studies; 16 557 participants) and clinical (46 studies; 3879 patient participants) samples and evaluated study quality. Ninety-three eligible articles considering 20 436 participants were retained for analysis. There was a robust association between dissociation and clinical and nonclinical positive psychotic symptoms (r = .437; 95%CI: .386 -.486), with the observed effect larger in nonclinical studies. Symptom-specific associations were also evident across clinical and nonclinical studies, and included significant summary effects for hallucinations (r = .461; 95%CI: .386 -.531), delusions (r = .418; 95%CI: .370 -.464), paranoia (r = .447; 95%CI: .393 -.499), and disorganization (r = .346; 95%CI: .249 -.436). Associations with negative symptoms were small and, in some cases, not significant. Overall, these findings confirm that dissociative phenomena are not only robustly related to hallucinations but also to multiple positive symptoms, and less robustly related to negative symptoms. Our findings are consistent with proposals that suggest certain psychotic symptoms might be better conceptualized as dissociative in nature and support the development of interventions targeting dissociation in formulating and treating psychotic experiences.