Mental Health Apps: Usage and Effectiveness Statistics

Open an app store and search “anxiety” or “depression,” and the results scroll on almost endlessly. Meditation timers, mood trackers, guided cognitive behavioral therapy programs, chatbots, breathing coaches — a peer-reviewed meta-review found that well over 10,000 mental health apps are now available for download (Lecomte et al., 2021). The National Institute of Mental Health similarly notes that “thousands of mental health apps are available” and that the number keeps growing (NIMH). Only a small number of these have been formally cleared by the U.S. Food and Drug Administration.

That abundance raises an obvious question: do these apps actually help? Because so many are marketed with confident claims and glossy testimonials, it is worth separating the marketing from the measured evidence. And here mental health apps have a genuine advantage over most digital-wellness topics — a large body of randomized controlled trials (RCTs) has tested them head to head against control conditions, which lets researchers make cause-and-effect statements about whether the apps themselves produce benefit.

This article walks through what that research shows: how many apps exist, how well they perform for depression and anxiety in clinical trials, and how many people actually keep using them. The short version is that apps deliver small but real benefits, struggle to hold users’ attention, and are best understood as a supplement to care rather than a replacement for it.

How Many Mental Health Apps Are There?

There is no official registry of mental health apps, so exact counts are impossible. The most defensible peer-reviewed figure is a floor: more than 10,000 mental health apps are available for download (Lecomte et al., 2021). NIMH’s federal guidance echoes this, describing “thousands” of apps spanning a wide range of purposes — from self-management and symptom tracking to skill-building and illness-management support (NIMH).

The catalog is vast, but oversight is thin. Most apps are consumer-wellness products that are not evaluated as medical devices. Only a small number have been formally FDA-cleared, which means the overwhelming majority reach users without the kind of regulatory review applied to prescription treatments. NIMH cautions that very few apps have been independently tested for effectiveness, and that a polished interface is not evidence that a tool works. That gap between the size of the market and the depth of the evidence is the central tension in this field.

Do Mental Health Apps Actually Work?

The strongest evidence comes from a 2024 meta-analysis in World Psychiatry that pooled 176 randomized controlled trials of mental health smartphone apps (Linardon et al., 2024). Across those trials, apps produced small but statistically significant improvements:

A few of these numbers deserve translation. Hedges’ g is a standardized measure of how large an effect is; by common convention, values around 0.2 are “small” and around 0.5 are “medium.” So the effects here — 0.28 for depression and 0.26 for anxiety — are real but modest (Linardon et al., 2024). The number needed to treat (NNT) describes how many people would have to use an app for one additional person to benefit compared with a control group: roughly 11 to 12 people in these analyses. When an app was specifically designed to target depression rather than treating it as a side benefit, the effect grew somewhat larger (g = 0.38). An earlier meta-review reached a compatible conclusion, finding that standalone smartphone apps were efficacious for anxiety and depression with small-to-medium effects (g ≈ 0.29) (Lecomte et al., 2021).

For context on the size of the populations these tools aim to help, see our overviews of how many people have depression and how many people have anxiety.

Why the Trial Design Matters

These figures carry more weight than the typical digital-wellness statistic because they come from randomized controlled trials. In an RCT, participants are randomly assigned to use an app or to a control condition, which allows researchers to attribute differences in outcomes to the app itself rather than to who happened to download it. In other words, this evidence supports a genuine cause-and-effect claim about the intervention — a stronger footing than the cross-sectional correlations that dominate research on social media and mental health or screen time and mental health.

The Important Caveat: Compared With What?

The headline benefits shrink considerably once you ask what the apps were compared against. Most of the positive results come from trials that pitted an app against a waitlist or no-treatment control. When the same meta-analysis looked only at trials comparing apps with active interventions — such as face-to-face therapy or an established web-based program — the app effects were small and no longer statistically significant (Linardon et al., 2024).

That distinction matters enormously. It suggests an app may be better than nothing, but the evidence does not show it outperforming, or even reliably matching, conventional care. For someone with a diagnosable condition, an app is not a demonstrated substitute for therapy or medication.

The Engagement Problem: How Many People Keep Using Them

Even a well-designed app only helps if people keep opening it, and this is where mental health apps consistently stumble. In the World Psychiatry meta-analysis, the weighted average dropout rate from app conditions across 182 trial arms was 23.6% — roughly one in four participants (Linardon et al., 2024). After removing very small studies that can distort the average, dropout rose to about 29.9%, closer to three in ten.

An earlier analysis focused specifically on smartphone apps for depressive symptoms found a mean dropout of 26.2% across RCTs (Torous et al., 2020) — a pre-2021 figure, but consistent with the more recent estimate. And it is worth remembering that these dropout numbers come from controlled trials, where participants are supported, reminded, and often compensated. Real-world retention outside a study setting is generally understood to be lower still. An app’s measured benefit assumes a level of sustained use that many people never reach on their own.

Apps as a Supplement, Not a Substitute

Put the pieces together and a balanced picture emerges. Mental health apps are enormously abundant, easy to access, and low-cost, and clinical trials confirm they can produce small, real improvements in depression and anxiety symptoms. But those benefits are modest, they fade when apps are compared with active treatment, and a large share of users stop engaging within weeks.

NIMH frames digital tools accordingly: apps can extend the reach of mental health support — offering convenience, privacy, and around-the-clock availability — but they are best viewed as one part of a broader care plan, not a replacement for professional evaluation and treatment (NIMH). This is especially relevant given how many people go without any care at all. As we cover in our analysis of the mental health treatment gap, a large share of U.S. adults with any mental illness receive no treatment in a given year. Apps can help fill part of that gap for milder symptoms and can complement therapy, but they do not close it.

For anyone weighing an app, the practical takeaway is to treat it as a low-stakes supplement — a way to build skills, track depression or anxiety symptoms, or reinforce what happens in therapy — while keeping expectations grounded in what the trials actually show.

Frequently Asked Questions

How many mental health apps are there?

A peer-reviewed meta-review estimated that well over 10,000 mental health apps are available for download, and NIMH describes “thousands” of apps that continue to grow in number (Lecomte et al., 2021; NIMH). There is no official registry, so these figures represent conservative estimates rather than exact counts.

Do mental health apps actually work?

In a meta-analysis of 176 randomized controlled trials, apps produced small but statistically significant improvements in depression (g = 0.28) and anxiety (g = 0.26), with a number needed to treat of roughly 11 to 12 (Linardon et al., 2024). The effects are real but modest, and they were larger when depression was the app’s specific target (g = 0.38).

Are mental health apps as good as therapy?

The evidence does not show that. When apps were compared with active interventions like face-to-face or web-based therapy rather than a waitlist, their benefits were small and no longer statistically significant (Linardon et al., 2024). Apps appear better than nothing but are not a demonstrated substitute for conventional treatment.

How many people stop using mental health apps?

In clinical trials, the average dropout from app conditions was about 23.6% — roughly one in four — rising to around 29.9% after excluding very small studies (Linardon et al., 2024). An earlier analysis of apps for depressive symptoms found a comparable 26.2% dropout rate (Torous et al., 2020). Real-world retention outside of studies is generally believed to be lower.

Are mental health apps regulated by the FDA?

Only a small number of mental health apps have been formally cleared by the FDA. The large majority are marketed as consumer-wellness products and are not reviewed as medical devices, which is why NIMH advises that a polished app is not proof that a tool is effective (NIMH).

Sources

1. Linardon J, et al. Current evidence on the efficacy of mental health smartphone apps: a meta-analysis of 176 RCTs. World Psychiatry. 2024. https://onlinelibrary.wiley.com/doi/full/10.1002/wps.21183

2. Lecomte T, et al. Mobile Apps for Mental Health Issues: Meta-Review of Meta-Analyses. npj Digital Medicine. 2021. https://www.nature.com/articles/s41746-021-00386-8

3. Torous J, et al. Dropout rates in clinical trials of smartphone apps for depressive symptoms. J Affect Disord. 2020. https://pubmed.ncbi.nlm.nih.gov/31655388/

4. National Institute of Mental Health. Technology and the Future of Mental Health Treatment. NIMH. https://www.nimh.nih.gov/health/topics/technology-and-the-future-of-mental-health-treatment