Most trials of mental-health apps compare the app against nothing, or against a waiting list, which is a low bar dressed up as a control. A trial published in the Journal of affective disorders in 2026 did something more demanding: it compared an AI-powered anxiety app against an NHS self-help website, which is a real thing that real people are actually pointed towards. [pubmed-anxiety-jun23-2026-source]
What the researchers did
Three hundred and sixteen adults aged 19 to 70 with generalised anxiety were randomly assigned to either the app or a national health service website. Anxiety and depression were measured with the GAD-7 and PHQ-9 at the start and then at two, eight and twelve weeks.
The app offered CBT-informed conversational exchanges and interactive tools rather than a static library of advice, which is the difference the trial was built to test.
What they found
By two weeks, the app group had lower anxiety and depression scores than the website group, with medium effect sizes. That is fast.
At eight weeks, people still using the app showed clear reductions in both. Notably, those who had stopped using it still showed medium improvements in anxiety, which suggests at least some of what they learned came with them.
At twelve weeks the differences held, with moderate to large effect sizes.
The number the summary buries
Attrition was 33 per cent in the app group and 18.5 per cent in the website group. By twelve weeks, retention across the study was 54 per cent.
This matters more than any effect size, and it is the thing to hold onto. People stop using an app when it is not doing anything for them, so the group still present at the end is enriched for people it suited. Every benefit measured afterwards is measured on that filtered group. The honest reading is not that the app produces these effects in anyone who downloads it, but that it produces them in the roughly two thirds who keep going.
That the app group dropped out more than the website group is also worth sitting with, given the website is the less engaging product on paper.
How much weight to give it
The researchers call it exploratory and that is accurate. Nobody was blinded: everyone knew which arm they were in, and self-reported symptom scores are exactly the kind of outcome that responds to knowing you were given the interesting thing.
What the design gets right is the comparison. Beating an NHS self-help website is a more meaningful result than beating a waiting list, because it is the choice a person is actually making.
What this means in practice
If you are waiting for therapy, a structured interactive tool is a reasonable thing to use in the meantime, and this trial suggests it beats reading a static page. Two weeks is a fair window in which to judge whether it is doing anything for you.
What it should not do is replace an assessment. An app that helps is good news; an app that lets a problem run for another six months without anyone qualified looking at it is not.
Is a self-help tool the right level for this?
Tick anything that has been true for most of the last month.
0 of 6 ticked
Persistent, spreading anxiety that is changing what you do is what CBT and medication have the strongest evidence for. An app is a reasonable thing to use alongside that, and not a reasonable thing to use instead of getting it assessed.
Give it two weeks, which is when this trial first detected a difference. If nothing has shifted by then, that is information rather than failure, and it is worth taking to a doctor.
At this level the low-cost, immediately available option is the sensible first move. Keep an eye on whether the list above grows.
The source
These findings are drawn from “An exploratory randomized controlled trial of an AI-enabled mental health intervention for generalized anxiety” (Allen A, Young AH, Jellesma FC, et al., 2026), published in the Journal of affective disorders. Read the full study on PubMed.