What works best? A meta‐analysis exploring the efficacy of different types of cognitive behaviour therapy for generalized anxiety disorder

OBJECTIVES: Generalized anxiety disorder (GAD) is a common and debilitating anxiety disorder. Currently, several cognitive and/or behavioural models propose mechanisms that perpetuate GAD symptoms, but little is known about which model (and associated treatment) results in the best treatment outcomes. The aim of this study was to examine this research question using a meta-analytic approach. METHODS: Twenty-six studies (with 34 comparisons) were included in the meta-analysis covering six theoretical models. Within-group effect sizes were calculated using random effects models. Planned moderator analyses were conducted to determine whether there were any significant differences between models. RESULTS: The pooled within-group effect size was large across all treatment groups from pre-treatment to post-treatment (g = 1.591; 95% CI: 1.408-1.774); however, the treatment model used did moderate outcome (p = 0.002). A significant difference was found between the avoidance model of worry (AMW) and the meta-cognitive model (MCM) (p = 0.009), as well as the AMW and the intolerance of uncertainty model (IUM) (p < 0.001). There was no significant difference between the MCM and IUM. The within-group effect size from pre-treatment to follow-up remained large across all studies (g = 1.478; 95% CI: 1.307-1.649), and the treatment model used did not moderate outcomes at follow-up (p = 0.147). CONCLUSIONS: These findings demonstrate that while the short-term treatments used in the MCM and IUM may be more effective than the AMW, there are no significant differences in long-term outcomes. Therefore, any of the treatment approaches associated with the common GAD models are suitable for treating patients with GAD. REGISTRATION: The study was registered with the Prospero International prospective register of systematic reviews (PROSPERO) registration no. CRD42024595891.