Mobile applications (apps) have become an integral part of mental health support across various demographics. A comprehensive search strategy using academic databases was employed to identify relevant studies. Studies were assessed for methodological rigor and relevance to the research question. Mobile app usage by youths in Lagos was predominantly found to be around two-thirds (65%) of surveyed participants, with notable usage spikes during school breaks. Findings suggest a significant correlation between regular use of mental health apps and improved mental well-being among youth in Lagos. Further research should focus on developing culturally tailored mobile interventions to better serve the unique needs of youth in Nigeria. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.