Shift workers and people with sleep apnea seem to benefit about as much
In shift workers, the picture is fairly consistent. A review of 11 studies of digital CBT-I in shift-working populations found that sleep quality improved in every study but one, and two of those studies suggested the digital format was as effective as seeing a therapist in person [1]. That matters because irregular hours are exactly the situation where attending weekly clinic appointments is hardest, and users said they wanted more individualized feedback and customization to stay engaged [1].
For sleep apnea, the relevant group is people who have insomnia alongside mild-to-moderate obstructive sleep apnea, a combination clinicians call COMISA. In one randomized trial, 20 participants who completed a self-guided, culturally adapted and personalized digital CBT-I program were split into 7 with mild-to-moderate apnea and 13 with insomnia alone. Both groups improved substantially on insomnia severity right after treatment and at 1, 3, and 6 months, with large effect sizes, and the two groups did not differ significantly at any of those points [2]. Sleep diary measures such as time awake after falling asleep and sleep efficiency, plus depressive symptoms, also improved in both groups [2].
One caution belongs right next to that result: the apnea group had only seven people, and the authors note that small numerical differences between groups may simply reflect limited statistical power. They call for larger studies to determine whether people with apnea truly respond the same way [2]. So the finding is best read as "no detectable difference in a small trial," not proof of equivalence.
Chronic pain is the gap: the trial hasn't reported yet
For chronic pain, there is no outcome evidence to weigh. The one directly relevant study is a protocol, not a completed trial: a randomized controlled trial in Norway testing digital CBT-I added to usual physiotherapy versus physiotherapy alone in patients with chronic musculoskeletal complaints and insomnia [3]. It plans to enroll 188 people and measure insomnia severity at three months, with pain intensity, physical function, work ability, and medication use as secondary outcomes [3]. Until those results are published, any claim that digital CBT-I works as well for chronic pain would be extrapolation.
The rationale for expecting it might help is plausible but untested here: the protocol notes that insomnia is common among physiotherapy patients with musculoskeletal complaints and is associated with poorer pain prognosis, and that CBT-I may improve both sleep and pain-related outcomes [3]. That is a hypothesis the trial is designed to test, not a finding.
The evidence covers narrower groups than the question implies
It is worth being precise about who was actually studied. The shift-work review covered shift-working populations specifically [1]. The apnea analysis included only people with mild-to-moderate apnea, not those with severe apnea or those using CPAP, and it was a secondary analysis of a larger trial rather than a trial designed for that comparison [2]. The chronic pain trial, when it reports, will cover musculoskeletal complaints seen in primary-care physiotherapy in Norway [3].
A separate randomized trial compared a digital CBT-I adapted for shift workers against standard CBT-I, but its available description indicates it excluded people with sleep apnea, restless legs syndrome, or chronic pain, along with those with a history of severe mental disorders [4]. That exclusion is itself informative: much of the cleanest digital CBT-I evidence comes from people without these complicating conditions, which is exactly why the shift-worker and apnea results above are worth noting separately.
The practical takeaway is that digital CBT-I looks like a reasonable first option for insomnia in shift workers and in people with mild-to-moderate apnea, with the caveat that the apnea comparison rests on a small sample [1][2]. For chronic pain, the sensible stance is to wait for the ongoing trial rather than assume the benefit carries over [3].
Sources used in this answer
The Effects of Digital-Based Cognitive Behavioral Therapy for Insomnia (CBT-I) on Sleep Quality in Shift Workers: A Scoping Review.
A scoping review of 11 studies found that digital CBT-I improved sleep quality in shift workers in all but one study, and two studies suggested it was as effective as in-person CBT-I.
Exploring the effect of a culturally adapted and personalized digital CBT-I app in insomnia patients with mild-to-moderate OSA: a secondary analysis of a randomized controlled trial.
In a small secondary analysis of a randomized trial, a personalized digital CBT-I program improved insomnia severity, sleep diary measures, and depressive symptoms similarly in people with mild-to-moderate sleep apnea and in people with insomnia alone, with no significant group differences.
Effectiveness of digital Cognitive-Behavioural Therapy for Insomnia in patients with musculoskeletal complaints and insomnia in primary care physiotherapy: study protocol for a randomised controlled trial.
A study protocol describes an ongoing randomized trial testing whether digital CBT-I added to physiotherapy improves insomnia severity and pain-related outcomes in patients with chronic musculoskeletal complaints and insomnia; no results are reported yet.
… a CBT-I developed for shift workers (CBT-IS) to standard CBT-I (cognitive behavioural therapy for insomnia) on sleep onset latency, total sleep time, subjective sleep …
A randomized trial compared a digital CBT-I adapted for shift workers with standard CBT-I on sleep outcomes, but its described sample excluded people with sleep apnea, restless legs syndrome, chronic pain, and a history of severe mental disorders.
The effects of a CBT-I based app-program on sleep quality, insomnia severity, psychological strain and quality of life: A first efficacy study
A first efficacy study reported that a digital CBT-I app program can have substantial effects on sleep- and health-related outcomes, in a population that did not include chronic pain, sleep apnea, or shift work.