App-based insomnia therapy works — and lifts mood too

Insomnia and depression often travel together, and each can feed the other. Cognitive behavioural therapy for insomnia (CBT-I) is regarded as an effective and safe way of tackling both, but traditional delivery requires a trained therapist and repeated in-person sessions — a genuine bottleneck given how common insomnia is. Digital delivery, through apps and online programmes, could remove that bottleneck entirely, but only if it works as well as the real thing. Whether digitally delivered CBT-I holds up against face-to-face therapy was the question this meta-analysis set out to answer.

The researchers systematically searched the PubMed, Cochrane, Embase and Web of Science databases up to 5 June 2022 for randomised controlled trials of digital CBT-I in adults with insomnia and depression. Seven studies met the inclusion criteria, together involving 3,597 participants. The effects of digital CBT-I on insomnia severity and depression severity were pooled and expressed as standardised mean differences, with outcomes examined over both short and longer terms.

Digital CBT-I reduced insomnia severity substantially in the short term (SMD -0.85) and also mitigated depression (SMD -0.47). Both effects persisted over the longer term, at slightly reduced magnitudes: -0.71 for insomnia and -0.42 for depression. Notably, the effect of digital delivery was comparable to that of traditional face-to-face CBT-I, and improvements were generally maintained at follow-ups ranging from 6 weeks to 6 months. Across both timeframes, the effect on insomnia was consistently larger than the effect on depression.

CBT-I's effectiveness delivered in person was already well established; the open question was whether stripping out the therapist's physical presence would dilute it. This pooled analysis suggests it does not — digital delivery matched face-to-face therapy in these trials. That extends the evidence base for scalable insomnia treatment and supports the authors' conclusion that digital CBT-I might be considered a viable treatment option for depression as well. With only seven trials included and follow-up capped at 6 months, durability beyond that window remains an open question.

If poor sleep and low mood are tangled together for you, this is evidence that a structured digital programme built on CBT-I principles can meaningfully improve both — and that choosing digital over in-person delivery does not appear to mean settling for a weaker version. The larger effect on insomnia than depression is worth noting: sleep is where this intervention hits hardest. As ever with pooled trial data, individual programmes vary, and this analysis speaks to the approach rather than any single app.