The impact of psychological treatment on intolerance of uncertainty in generalized anxiety disorder: A systematic review and meta-analysis

Research has demonstrated a strong link between intolerance of uncertainty and generalized anxiety disorder (GAD). The current systematic review and meta-analysis aimed to evaluate how effective evidence-based psychological treatments are at reducing intolerance of uncertainty for adults with GAD. An extensive literature search identified 26 eligible studies, with a total of 1199 participants with GAD. Psychological treatments (k = 32 treatment groups) yielded large significant within-group effect size from pre- to post-treatment and pre-treatment to follow-up for intolerance of uncertainty (g = 0.88; g = 1.05), as well as related symptoms including worry (g = 1.32; g = 1.45), anxiety (g = 0.94; g = 1.04) and depression (g = 0.96; g = 1.00). Psychological treatment also yielded a large significant between-group effect on intolerance of uncertainty (g = 1.35). Subgroups analysis found that CBT that directly targeted intolerance of uncertainty (CBT-IU) throughout treatment was significantly more effective than general CBT at reducing intolerance of uncertainty (p < 0.01) and worry (p < 0.01) from pre- to post treatment, however, this result was not maintained at follow-up. Meta-regression analyses supported this finding as increases in the amount of time spent directly targeting intolerance of uncertainty, significantly increased the effect size for both intolerance of uncertainty (z = 2.01, p < 0.01) and worry (z = 2.23, p < 0.01). Overall, these findings indicate that psychological treatments are effective at reducing IU, and related symptom measures of GAD.