A meta-analysis on the efficacy of low-intensity cognitive behavioural therapy for generalised anxiety disorder

Low-intensity cognitive behavioural therapy (LICBT) has been recommended as a primary intervention in the tiered care for mild to moderate generalised anxiety disorder. However, LICBT for generalised anxiety disorder are markedly diverse and efficacy data on various outcomes have not been systematically reviewed. This meta-analysis aimed to synthesise effect sizes of three NICE-recommended LICBT for generalised anxiety disorder: non-facilitated self-help, guided self-help, and psychoeducational groups. A systematic literature review of randomised controlled trials (RCTs) examining LICBT for generalised anxiety disorder in the last 23 years (2000–2023) was conducted. Efficacy data for anxiety, depression, and worry outcomes were separately meta-analysed. The study was reported following the PRISMA guidelines. The systematic review identified 12 RCTs out of 1205 papers. The three meta-analyses consisted of 12 (anxiety), 11 (depression), and 9 (worry) effect sizes respectively, including total sample sizes of 1201 (anxiety), 1164 (depression), and 908 (worry). The adjusted effect sizes for reductions in anxiety (g = -0.63), depression (g = -0.48), and worry (g = -0.64) were all in the medium range, favouring LICBT over control conditions. Between-study heterogeneity was significant on anxiety and worry, with no specific moderators identified by meta-regression. LICBT has shown promise as an effective and efficient treatment modality for individuals with generalised anxiety disorder. Future research comparing various LICBT subtypes and treatment components will further inform clinical practice. This systematic review protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO; record ID CRD42021285590).