Trial reportJMIR mHealth and uHealth2021
Induction of Efficacy Expectancies in an Ambulatory Smartphone-Based Digital Placebo Mental Health Intervention: Randomized Controlled Trial.
Trial report in JMIR mHealth and uHealth, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT02365220 (Smartphone Application, Mood and Stress), which is not on this map. Cited by 10 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Smartphone Application, Mood and Stress
Who cites it
10 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Efficacy of prescription-eligible digital health applications for depression and generalized anxiety disorder in Germany: a systematic review and meta-analysis.Scientific reports · 2026Pooled it
- Evaluating a brief smartphone-based stress management intervention with heart rate biofeedback from built-in sensors in a three arm randomized controlled trial.Scientific reports · 2025Trial
- Does outcome expectancy predict outcomes in online depression prevention? Secondary analysis of randomised-controlled trials.Health expectations : an international journal of public participation in health care and health policy · 2024Trial
- Increasing the Effectiveness of a Physical Activity Smartphone Intervention With Positive Suggestions: Randomized Controlled Trial.Journal of medical Internet research · 2022Trial
- Digital Therapeutic Content for Substance Use Disorder Treatment: Development and Evaluation Study.JMIR formative research · 2026Article
- Digital Wellness Programs in the Workplace: Meta-Review.Journal of medical Internet research · 2025Review
- Credibility and expectancy of smartphone-based cognitive behavioral therapy among adults with body dysmorphic disorder.Journal of obsessive-compulsive and related disorders · 2023Article
- Cognitive reappraisal in mHealth interventions to foster mental health in adults: a systematic review and meta-analysis.Frontiers in digital health · 2023Review
- [Development, Evaluation and Implementation of Digital Health Interventions (Part 1) - Discussion Paper of the Digital Health Working Group of the German Network for Health Services Research (DNVF)].Gesundheitswesen (Bundesverband der Arzte des Offentlichen Gesundheitsdienstes (Germany)) · 2023Article
- Eating disorders early app use mediates treatment effect on clinical improvement.The International journal of eating disorders · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThere is certain evidence on the efficacy of smartphone-based mental health interventions. However, the mechanisms of action remain unclear. Placebo effects contribute to the efficacy of face-to-face mental health interventions and may also be a potential mechanism of action in smartphone-based interventions.
objectiveThis study aimed to investigate whether different types of efficacy expectancies as potential factors underlying placebo effects could be successfully induced in a smartphone-based digital placebo mental health intervention, ostensibly targeting mood and stress.
methodsWe conducted a randomized, controlled, single-blinded, superiority trial with a multi-arm parallel design. Participants underwent an Android smartphone-based digital placebo mental health intervention for 20 days. We induced prospective efficacy expectancies via initial instructions on the purpose of the intervention and retrospective efficacy expectancies via feedback on the success of the intervention at days 1, 4, 7, 10, and 13. A total of 132 healthy participants were randomized to a prospective expectancy-only condition (n=33), a retrospective expectancy-only condition (n=33), a combined expectancy condition (n=34), or a control condition (n=32). As the endpoint, we assessed changes in efficacy expectancies with the Credibility Expectancy Questionnaire, before the intervention and on days 1, 7, 14, and 20. For statistical analyses, we used a random effects model for the intention-to-treat sample, with intervention day as time variable and condition as two factors: prospective expectancy (yes vs no) and retrospective expectancy (yes vs no), allowed to vary over participant and intervention day.
resultsCredibility (β=-1.63; 95% CI -2.37 to -0.89; P<.001) and expectancy (β=-0.77; 95% CI -1.49 to -0.05; P=.04) decreased across the intervention days. For credibility and expectancy, we found significant three-way interactions: intervention day×prospective expectancy×retrospective expectancy (credibility: β=2.05; 95% CI 0.60-3.50; P=.006; expectancy: β=1.55; 95% CI 0.14-2.95; P=.03), suggesting that efficacy expectancies decreased least in the combined expectancy condition and the control condition.
conclusionsTo our knowledge, this is the first empirical study investigating whether efficacy expectancies can be successfully induced in a specifically designed placebo smartphone-based mental health intervention. Our findings may pave the way to diminish or exploit digital placebo effects and help to improve the efficacy of digital mental health interventions.
trial registrationClinicaltrials.gov NCT02365220; https://clinicaltrials.gov/ct2/show/NCT02365220.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.