Yasuko Inoue

BACKGROUND: Foster parents' unique challenges significantly impact their mental health, which in turn influences child well-being and placement stability. Although various intervention programs have been developed to support foster families, research specifically targeting foster parents' mental health as a primary outcome remains limited. Previous reviews have examined parenting stress, leaving a gap in understanding the effectiveness of interventions addressing broader mental health domains such as depression and anxiety. This systematic review aims to evaluate the efficacy of foster parent training programs in improving psychological distress, depression, anxiety, and stress. METHODS: This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 guidelines and is registered with the Open Science Framework. Information sources will include MEDLINE, CENTRAL, PsycINFO, and Embase, searched from inception to May 2023. An updated search will be conducted prior to final analysis. The review will include randomized controlled trials published in peer-reviewed English-language journals. Eligible interventions will include structured training, educational, or support programs for foster parents. Eligible comparators will include any control condition (e.g., usual care, waitlist, no intervention) or other active interventions. Primary outcomes will include psychological distress, depression, anxiety, and stress. Secondary outcomes will assess family-related psychological outcomes. Risk of bias will be assessed using the Cochrane Risk of Bias Tool (RoB 2) and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Data will be synthesized using meta-analysis when appropriate; otherwise, narrative synthesis will be conducted the Synthesis Without Meta-analysis (SWiM) guidelines. Subgroup analyses will explore differential effects by theoretical framework and specific mental health outcomes. The review began on May 14, 2023, with an anticipated completion date of August 31, 2025. The study is supported by Japan Society for the Promotion of Science (JSPS) KAKENHI, Grant-in-Aid for Scientific Research (B), Grant Number JP21H03253. DISCUSSION: This systematic review will evaluate interventions targeting foster parents' mental health across multiple psychological dimensions, surpassing the limited scope of prior studies. The rigorous methodology aims to inform the development of evidence-based mental health support programs for foster parents. SYSTEMATIC REVIEW REGISTRATION: Open Science Framework ( https://osf.io/qzd43 ).