Abstract
Insomnia impairs daily functioning and increases health risks. Cognitive behavioral therapy for insomnia (CBT-I) is effective but limited by cost and therapist availability. Fully automated digital CBT-I (FA dCBT-I) provides an accessible alternative without therapist involvement. This systematic review and meta-analysis evaluated the effectiveness of FA dCBT-I across 29 randomized controlled trials (RCTs) involving 9475 participants. Compared to control groups, FA dCBT-I demonstrated moderate to large effects on insomnia severity. Subgroup analyses indicated that FA dCBT-I had a significant impact when contrasted with most control groups but was less effective than therapist-assisted CBT-I. Meta-regression revealed that control group type moderated outcomes, whereas completion rate did not. This implies that treatment adherence, rather than merely completing the intervention, is crucial for its effectiveness. This study supports the potential of FA dCBT-I as a promising option for managing insomnia but underscores that a hybrid model combining therapist support is more beneficial.