Targeting intolerance of uncertainty in treatment: A meta-analysis of therapeutic effects, treatment moderators, and underlying mechanisms

Anxiety-related disorders are among the most prevalent psychiatric conditions and cause significant impairment. Intolerance of uncertainty (IU) contributes to the emergence, maintenance, and symptom severity of anxiety-related disorders, yet information regarding treatment-related changes in IU is limited. This systematic review and meta-analysis examined the efficacy of evidence-based treatments for anxiety-related disorders on IU, explored factors moderating treatment effects of IU, and examined whether therapeutic improvement in IU corresponded with improvements in anxiety symptom severity.PubMED and PsycINFO were searched for randomized controlled trials (RCTs) using the terms "intolerance of uncertainty" AND "treatment" OR "therapy." Data for pre and post-treatment measures and patient, intervention, and trial-level characteristics were extracted from 28 RCTs. Separate random effects models examined the treatment efficacy of interventions on IU and symptom severity. Moderators of therapeutic effects were analyzed via method-of-moments meta-regression or an analog to the analysis of variance.Across RCTs, interventions exhibited a large therapeutic effect on IU compared to control conditions (g = 0.89). Treatment effects on IU positively corresponded with improved symptom severity and accounted for 36 % of the variance. Interestingly, comorbid depression and certain treatment approaches were associated with larger improvements in IU.Evidence-based treatments are effective in improving IU, highlighting the importance of IU in the treatment of anxiety-related disorders. Moderator analyses identified patient and intervention-level factors to inform approaches to improve therapeutic effects on IU. Future research is needed to optimize interventions targeting IU and evaluate long-term efficacy of interventions on IU for anxiety-related disorders.