Mobile Apps That Promote Emotion Regulation, Positive Mental Health, and Well-being in the General Population: Systematic Review and Meta-analysis

Background: Among the general public there appears to be a growing need and interest in receiving digital mental health and wellbeing support. In response to this, a number of mental health apps (MHapps) are becoming available for monitoring, managing and promoting positive mental health and wellbeing. Thus far, the evidence supports positive outcomes when users engage with digital interventions. However, there is high variability in the theoretical base informing MHapps and the features incorporated. Such differences can have implications for the efficacy of the apps and the level of engagement among specific target population groups. Moreover, such heterogeneity may influence the extent to which the data from various MHapps can be pooled to assess the strength of the evidence.Objective: We aimed to systematically review the available research on MHapps that promote emotion regulation, positive mental health, and wellbeing in the general population aged 18-45. More specifically, the review aimed at providing a systematic description of the theoretical background and features of MHapps while evaluating any potential effectiveness.Methods: A comprehensive literature search of key databases; MEDLINE (via Ovid), EMBASE (via Ovid), PsycINFO (via Ovid), Web of Science, and the Cochrane Register of Controlled Trials(CENTRAL) was conducted until January 2021. Studies were included if they described standalone mental health and wellbeing apps for adults without a formal mental health diagnosis. All studies were quality assessed against the Mixed Methods Appraisal Tool. In addition, the Cochrane risk-ofbias tool (RoB-2) was used to assess randomized control trials (RCTs). Data were extracted using a modified extraction form from the Cochrane Handbook of Systematic Reviews. A narrative synthesis and meta-analysis were then undertaken to address the review aims.Results: In total, 3156 abstracts were identified. Of these, 52 publications describing 48 MHapps met the inclusion criteria. Together the studies evaluated interventions across 15 countries. Thirty-nine RCTs were identified that suggested there is some support for the role of individual MHapps in improving and promoting mental health and wellbeing. Regarding pooled effect, MHapps, when compared to controls, showed a small effect for reducing mental health symptoms (k = 19, g = -0.24, 95% CI [-0.34, -0.14], p < .05) and improving wellbeing (k = 13, g = 0.17, 95% CI [0.05, 0.29], p <.05), and a medium effect for emotion regulation (k = 6, g = 0.49, 95% CI [0.23,0.74], p<.05). There is also a wide knowledge base of creative and innovative ways to engage users in techniques, such as mood monitoring and guided exercises. Mindfulness and Cognitive Behavioural approaches appear to be the most common among MHapp developers. Studies were generally assessed to contributeunclear or high risk of bias, or be of medium to low methodological quality.Conclusions: This research contributes a review of the evidence for MHapps that promote positive mental health and wellbeing within the general population, in a relatively understudied area ofMHapp research. The emerging evidence for MHapps that promote positive mental health and wellbeing suggests evidence of promise. Despite a wide range of MHapps, there are not many apps that specifically promote emotion regulation. However, our findings may position emotion regulation as an important mechanism for inclusion in future MHapps. A fair proportion of the included studies were pilot or feasibility trials (k = 17, 33%), and full scale RCTs reported high attrition rates and nondiverse samples. Given the number and pace at which MHapps are being released, further robust research is warranted to inform the development and testing of evidence-based programs.