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

Objective: 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. Methods: 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. Results: 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. Conclusion: 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.