Background: Mental health problems are highly prevalent, and there is need for the self-management of (mental) health. Ecological momentary interventions (EMIs) can be used to deliver interventions in the daily life of individuals using mobile devices.
Objectives: The aim of this study was to systematically assess and meta-analyze the effect of EMI on 3 highly prevalent mental health outcomes (anxiety, depression, and perceived stress) and positive psychological outcomes (eg, acceptance).
Methods: PsycINFO and Web of Science were searched for relevant publications, and the last search was done in September 2015. Three concepts were used to find publications: (1) mental health, (2) mobile phones, and (3) interventions. A total of 33 studies (using either a within- or between-subject design) including 43 samples that received an EMI were identified (n=1301), and relevant study characteristics were coded using a standardized form. Quality assessment was done with the Cochrane Collaboration tool.
Results: Most of the EMIs focused on a clinical sample, used an active intervention (that offered exercises), and in over half of the studies, additional support by a mental health professional (MHP) was given. The EMI lasted on average 7.48 weeks (SD=6.46), with 2.80 training episodes per day (SD=2.12) and 108.25 total training episodes (SD=123.00). Overall, 27 studies were included in the meta-analysis, and after removing 6 outliers, a medium effect was found on mental health in the within-subject analyses (n=1008), with g=0.57 and 95% CI (0.45-0.70). This effect did not differ as function of outcome type (ie, anxiety, depression, perceived stress, acceptance, relaxation, and quality of life). The only moderator for which the effect varied significantly was additional support by an MHP (MHP-supported EMI, g=0.73, 95% CI: 0.57-0.88; stand-alone EMI, g=0.45, 95% CI: 0.22-0.69; stand-alone EMI with access to care as usual, g=0.38, 95% CI: 0.11-0.64). In the between-subject studies, 13 studies were included, and a small to medium effect was found (g=0.40, 95% CI: 0.22-0.57). Yet, these between-subject analyses were at risk for publication bias and were not suited for moderator analyses. Furthermore, the overall quality of the studies was relatively low.
Conclusions: Results showed that there was a small to medium effect of EMIs on mental health and positive psychological well-being and that the effect was not different between outcome types. Moreover, the effect was larger with additional support by an MHP. Future randomized controlled trials are needed to further strengthen the results and to determine potential moderator variables. Overall, EMIs offer great potential for providing easy and cost-effective interventions to improve mental health and increase positive psychological well-being.
Keywords: anxiety; depression; ecological momentary intervention; mHealth; mental health; meta-analysis; stress; systematic review.