Recent years have highlighted the increasing need to promote mental well-being in the general population. This has led to a rapidly growing market of fully automated digital mental well-being tools. Although many individuals have started using these tools in their daily lives, evidence on the overall effectiveness of digital mental well-being tools is currently lacking. The objective of the current study was therefore to review evidence on the effectiveness of fully automated digital interventions to promote mental well-being in the general population. Following preregistration of the systematic review protocol on PROSPERO (registration: CRD42022310702), searches were carried out in: Medline, Web of Science, Cochrane, PsychINFO, PsychEXTRA, Scopus and ACM Digital (initial searches in February 2022; updated in October 2022). Studies were included if they contained a general population sample and a fully automated digital intervention that exclusively employed psychological mental well-being promotion activities. Two reviewers, blinded to each other’s decisions, conducted data selection, extraction and quality assessment of the included studies. A narrative synthesis and a random-effects model of Per Protocol (PP) data were adopted. The study beckons a fresh understanding of the effectiveness, merits, and demerits of fully automated digital mental well-being interventions for the general populace. It accentuates the imperative for future research and practice to heed these findings while crafting new digital tools. A call to arms is made for further examination of positive psychology and cognitive behavioural therapy-based tools, along with the development of robust strategies to bolster adherence and curb dropout rates in these digital interventions. Ultimately, the quest to comprehend the specific circumstances and demographics where these interventions shine the brightest remains a pivotal avenue for ensuing research and practice.

Extensive searches were executed across various reputable databases such as MEDLINE, Web of Science, Cochrane, and others, from February to October 2022. The inclusion criteria centred on studies encompassing a general population sample and a fully automated digital intervention, focusing solely on activities promoting psychological mental well-being. A duo of blind reviewers undertook the data selection, extraction, and quality assessment of the identified studies, adopting a narrative synthesis and a random-effects model for per-protocol data.