BACKGROUNDWithin a decade, the expeditious evolution of technology has catalyzed digital advancements employed even at one’s fingertips. Now a household item, smartphones host innumerable apps supporting users across the world. One of the rising market niches includes mental-health based applications, which further branch into topics of lifestyle, habit-building, and productivity.METHODSThis systematic review explores quantitative and qualitative studies discussing variables of influence on social behaviours and trends for mental-health based applications. Searched databases include Science Direct, ProQuest, and Scopus with further supplementation of grey literature from Science Daily, Common Sense Media, and Extreme Networks. Extracted data precluded meta-analysis given the significant heterogeneity in study design, outcomes, and measurements. Studies were screened with a piloted tool and screening & extraction was completed independently among two authors. Disagreements following reconciliation between the two authors were settled by a third author. RESULTSAppraised articles identified trends & behaviors associated with app functionality, accessibility, and data/privacy security. The decline or absence of these features correlated with low user engagement.CONCLUSIONPrevalent features were determined for enhanced functionality, accessibility, and database security, which may serve to bolster apps within mental-health and its niches.