Small Interventions, Meaningful Change? A Systematic Review of Digital Mental Health Micro-Interventions

<p>Background: Digital mental health micro-interventions designed to be completed in 15 minutes or less may provide accessible, low-burden psychological support, yet the evidence is conceptually fragmented and has not been systematically synthesised.Objective: To characterise digital mental health micro-interventions lasting 15 minutes or less and synthesise evidence concerning their immediate and short-latency psychological effects, acceptability, feasibility, engagement, and safety.Methods: A systematic search of 4,064 identified independently deliverable digital therapeutic interventions lasting ≤15 minutes and assessing an immediate or short-latency psychological outcome. Following duplicate removal, 3,482 records were screened. Due to substantial clinical and methodological heterogeneity, findings were synthesised narratively.Results: Ten reports describing 11 independent studies published between 2017 and 2025 met eligibility criteria. Interventions incorporated behavioural activation, cognitive and emotion-regulation techniques, mindfulness, relaxation, distress tolerance, body-image content, and dialectical behaviour therapy skills. All were self-guided; six incorporated personalisation, but only one used momentary data to adapt delivery. Every study reported improvement in at least one eligible outcome, including mood, affect, distress, hopelessness, stress, body satisfaction, behavioural activation, or confidence. However, only four provided eligible controlled comparisons, sustained benefits were limited, and overall risk of bias was high. Common concerns included attrition, unblinded self-report, uncontrolled analyses, and selective reporting. Acceptability was generally favourable among users who engaged, although uptake and retention varied. Safety was inconsistently assessed.Conclusions: Digital micro-interventions show promise for producing immediate improvements in selected psychological states. However, the evidence remains small, heterogeneous, and frequently reliant on uncontrolled analyses. More rigorous controlled trials, standardised reporting, systematic safety monitoring, and research examining user receptivity are required.</p>