Current evidence on the efficacy of mental health smartphone apps for symptoms of depression and anxiety. A meta‐analysis of 176 randomized controlled trials

Summary & key facts

This meta-analysis combined 176 randomized controlled trials and found that mental health smartphone apps produced small but statistically significant reductions in depressive symptoms (g = 0.28, N = 33,567, NNT = 11.5) and generalized anxiety symptoms (g = 0.26, N = 22,394, NNT = 12.4). Effects were stronger for apps that used cognitive behavioral therapy (CBT), mood monitoring, or chatbots, and the main results held up at follow-up and after removing small or higher-bias trials. Some disorder-specific findings (for example, social anxiety, OCD, PTSD, acrophobia, panic) came from fewer and higher-risk studies and should be read with caution.

Key facts:

• The review pooled 176 randomized controlled trials of apps for depression or anxiety.
• Apps had a small but statistically significant effect on depressive symptoms: Hedges' g = 0.28, N = 33,567, p < 0.001, number needed to treat (NNT) = 11.5.
• Apps had a small but statistically significant effect on generalized anxiety symptoms: g = 0.26, N = 22,394, p < 0.001, NNT = 12.4.
• Outcome variability at post-test was lower in app groups than control groups: ratio of variance (RoV) = -0.14 for depression (95% CI: -0.24 to -0.05) and RoV = -0.21 for generalized anxiety (95% CI: -0.31 to -0.12).
• Effect sizes for depression were larger when apps included cognitive behavioral therapy (CBT) features or chatbot technology.
• Effect sizes for anxiety were larger when trials specifically targeted generalized anxiety and when apps used CBT or mood monitoring features.
• For other conditions, the meta-analysis reported g = 0.52 for social anxiety and g = 0.51 for obsessive-compulsive symptoms; g = 0.12 for post-traumatic stress symptoms; g = 0.90 for acrophobia; and a non-significant negative effect for pan
• The authors note that many of the disorder-specific results (social anxiety, OCD, PTSD, acrophobia, panic) were based on small samples and trials with higher risk of bias, so those specific estimates are less certain.
• The main findings for depression and generalized anxiety were robust across different follow-up times and remained after removing small-sample and higher-risk-of-bias trials.

Abstract

The mental health care available for depression and anxiety has recently undergone a major technological revolution, with growing interest towards the potential of smartphone apps as a scalable tool to treat these conditions. Since the last comprehensive meta-analysis in 2019 established positive yet variable effects of apps on depressive and anxiety symptoms, more than 100 new randomized controlled trials (RCTs) have been carried out. We conducted an updated meta-analysis with the objectives of providing more precise estimates of effects, quantifying generalizability from this evidence base, and understanding whether major app and trial characteristics moderate effect sizes. We included 176 RCTs that aimed to treat depressive or anxiety symptoms. Apps had overall significant although small effects on symptoms of depression (N=33,567, g=0.28, p<0.001; number needed to treat, NNT=11.5) and generalized anxiety (N=22,394, g=0.26, p<0.001, NNT=12.4) as compared to control groups. These effects were robust at different follow-ups and after removing small sample and higher risk of bias trials. There was less variability in outcome scores at post-test in app compared to control conditions (ratio of variance, RoV=-0.14, 95% CI: -0.24 to -0.05 for depressive symptoms; RoV=-0.21, 95% CI: -0.31 to -0.12 for generalized anxiety symptoms). Effect sizes for depression were significantly larger when apps incorporated cognitive behavioral therapy (CBT) features or included chatbot technology. Effect sizes for anxiety were significantly larger when trials had generalized anxiety as a primary target and administered a CBT app or an app with mood monitoring features. We found evidence of moderate effects of apps on social anxiety (g=0.52) and obsessive-compulsive (g=0.51) symptoms, a small effect on post-traumatic stress symptoms (g=0.12), a large effect on acrophobia symptoms (g=0.90), and a non-significant negative effect on panic symptoms (g=-0.12), although these results should be considered with caution, because most trials had high risk of bias and were based on small sample sizes. We conclude that apps have overall small but significant effects on symptoms of depression and generalized anxiety, and that specific features of apps - such as CBT or mood monitoring features and chatbot technology - are associated with larger effect sizes.

Topics

Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes Digital Mental Health Interventions Mental Health Research Topics

Categories

Applied Psychology Psychology Social Sciences

Tags

Anxiety Clinical psychology Depression (economics) Developmental psychology Economics Generalizability theory Internal medicine Macroeconomics Medicine Mental health Meta-analysis Psychiatry Psychology Randomized controlled trial

Conditions & symptoms

Anxiety Depression Obsessive-Compulsive Disorder Panic disorder and phobias PTSD Anxiety or worry Panic Sadness or low mood