A systematic review of mental health apps for mobile devices found that some apps showed significant reductions in depression, stress, and substance use. The review included 8 studies of 5 apps targeting depression, anxiety, and substance abuse. Four apps provided support from mental health professionals. Results showed significant within-group and between-group effect sizes, though the majority of available apps lack scientific evidence. The review highlights the potential of mental health apps to improve treatment accessibility but notes the need for more rigorous research. Only two of the five evidence-based apps are currently available in app stores. The review also discusses the limitations of current studies, including small sample sizes, high risk of bias, and lack of long-term follow-up data. The findings suggest that while mental health apps may be effective, further research is needed to confirm their efficacy and ensure they meet scientific standards. The review emphasizes the importance of public education on identifying evidence-based mental health apps and the need for regulation in the rapidly growing field of mHealth.A systematic review of mental health apps for mobile devices found that some apps showed significant reductions in depression, stress, and substance use. The review included 8 studies of 5 apps targeting depression, anxiety, and substance abuse. Four apps provided support from mental health professionals. Results showed significant within-group and between-group effect sizes, though the majority of available apps lack scientific evidence. The review highlights the potential of mental health apps to improve treatment accessibility but notes the need for more rigorous research. Only two of the five evidence-based apps are currently available in app stores. The review also discusses the limitations of current studies, including small sample sizes, high risk of bias, and lack of long-term follow-up data. The findings suggest that while mental health apps may be effective, further research is needed to confirm their efficacy and ensure they meet scientific standards. The review emphasizes the importance of public education on identifying evidence-based mental health apps and the need for regulation in the rapidly growing field of mHealth.