Intolerance of Uncertainty in Eating Disorders: A Systematic Review and Meta-Analysis.

Intolerance of uncertainty is an empirically supported transdiagnostic construct that may have relevance in understanding eating disorders. We conducted a meta-analysis and systematic review of intolerance of uncertainty in eating disorders using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We calculated random-effects standardised mean differences (SMD) for studies utilising the Intolerance of Uncertainty Scale (IUS) and summarised additional studies descriptively. Women with eating disorders have significantly higher IUS scores compared with healthy controls (SMD = 1.90; 95% C.I. 1.24 to 2.56; p < 0.001). Post hoc meta-analysis revealed significant differences when comparing women with anorexia nervosa with controls (SMD = 2.16; 95% C.I. 1.14 to 3.18; p < 0.001) and women with bulimia nervosa with controls (SMD = 2.03; 95% C.I. 1.30 to 2.75; p < 0.001). Our synthesis of findings suggests that intolerance of uncertainty may represent a vulnerability and maintenance factor for eating disorders and potential target of cognitive, behavioural, interoceptive and affective symptoms.