A meta-analysis of randomized controlled trials (RCTs) depicted that cognitive behavioral therapy for insomnia (CBT-I) effectively improves total sleep time (TST) as measured by sleep diaries and polysomnography in individuals with insomnia. The target was to determine CBT-I effect on both subjective and objective TST.

To gather relevant literature, a systematic search was conducted, resulting in the inclusion of 43 RCTs for the meta-analysis. The presence of publication biases was examined. To investigate the impact of sample or treatment characteristics on effect sizes across trials, meta-regressions were performed.

The analysis revealed a modest average effect of CBT-I on diary-assessed TST at the end of treatment, indicating an approximate elevation of 30 minutes. The impact of CBT-I on polysomnography-measured and diary-measured TST was found to be influenced by age, with smaller effect sizes observed in older age groups. In contrast, a negative moderate effect size was observed for actigraphy-assessed TST, indicating a decline of approximately 30 minutes.

The presence of publication biases was detected for diary data in follow-up evaluations, indicating a tendency to favor positive findings. CBT-I led to enhancements in TST as assessed through polysomnography and sleep diaries in adults. However, these improvements were not supported by actigraphy measurements. The study discussed both theoretical and clinical implications of these findings.