Long-Term Effect of Cognitive Behavioral Therapy in Managing Subclinical Depression: A Systematic Review and Meta-Analysis.

Recent research has emphasized the continuum of depression, highlighting the significance of early intervention for subclinical depression. However, previous studies often focused on specific populations or lacked comparisons across participants and intervention characteristics in the effectiveness of cognitive behavioral therapy (CBT). This systematic review and meta-analysis (CRD42024498284) aimed to address these gaps by examining the effectiveness of CBT in managing subclinical depression and its potential for preventing the transition to major depression. A comprehensive search across seven databases from inception to March 2025, identified 23 randomized controlled trials (RCTs) involving 5877 participants. Meta-regression, sensitivity analysis, and funnel plots were utilized to assess heterogeneity, publication bias, and study quality. CBT significantly improved subclinical depressive symptoms (at postassessment:  = -0.89; 95% confidence interval (CI) = -1.57 to -0.20 and follow-up:  = -0.56; 95% CI: -0.93 to -0.18) and anxiety symptoms (at postassessment:  = -0.92; 95% CI: -1.84 to -0.00 and follow-up:  = -0.70; 95% CI: -1.15 to -0.25), but had no notable impact on quality of life. Meta-regression analysis identified the number of CBT sessions as factors influencing CBT effectiveness in managing depressive symptoms. While there are statistically significant results (RR = 0.62; 95% CI = 0.50-0.77) indicating CBT's preventive efficacy in transitioning from subclinical to major depression, evidences were limited by the self-reporting data. The majority of included studies came from Europe which limited generalizability, and comparisons between different types of CBT, education levels, and CBT components were limited. In general, CBT has been demonstrated to be effective in managing depressive symptoms over time. Additional research, particularly from diverse regions and comparative studies between CBT and alternative treatments, is imperative to overcome the current study's limitations.