Is Cognitive Behavioral Therapy for Insomnia Effective for Improving Sleep Duration in Individuals with Insomnia? A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND
Accumulating evidence suggests that sleep duration is a critical determinant of physical and mental health. Half of the individuals with chronic insomnia report less than optimal sleep duration. Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment for reducing sleep difficulties in individuals with chronic insomnia. However, its effectiveness for increasing sleep duration is less well-established and a synthesis of these findings is lacking.


PURPOSE
To provide a synthesis of findings from randomized controlled trials (RCTs) on the effect of CBT-I on subjective and objective total sleep time (TST).


METHODS
A systematic search was performed on articles published from 2004 to 05/30/2021. A total of 43 RCTs were included in the meta-analysis. Publication biases were examined. Meta-regressions were conducted to examine if any sample or treatment characteristics moderated the effect sizes across trials.


RESULTS
We found a small average effect of CBT-I on diary-assessed TST at post-treatment, equivalent to an approximately 30-min increase. Age significantly moderated the effects of CBT-I on diary-measured and polysomnography-measured TST; older ages were associated with smaller effect sizes. Contrarily, a negative, medium effect size was found for actigraphy-assessed TST, equivalent to an approximately 30-min decrease. Publication biases were found for diary data at follow-up assessments suggesting that positive findings were favored.


CONCLUSIONS
CBT-I resulted in improvements in TST measured by sleep diaries and polysomnography (in adults). These improvements were not corroborated by actigraphy findings. Theoretical and clinical implications were discussed.