Psychological flexibility, mental health, and resilience outcomes: a systematic review and meta-analysis

Psychological flexibility (PF) is gaining recognition as a transdiagnostic psychological process linked to mental well-being and functioning. The current systematic review and meta-analysis provide synthesis of literature on the relationships between PF and depression, anxiety, stress/burnout, and resilience. In line with PRISMA 2020 guidelines, studies published from January 2010 to December 2025 were retrieved from the Scopus, Web of Science, PubMed, and PsycINFO databases. Thirty-nine studies satisfied the inclusion criteria for the systematic review, eight of which offered sufficient quantitative comparisons for meta-analysis. According to random-effects models, moderate negative relationships were found between PF and depression (r = −0.48), anxiety (r = −0.47), and stress/burnout (r = −0.46), and a positive relationship with resilience (r = 0.51). Very high heterogeneity was detected for depression (I2 = 90.9%), anxiety (I2 = 90.8%), and stress/burnout (I2 = 91.1%), while lower heterogeneity for resilience (I2 = 34.6%) indicates considerable diversity of contextual and methodological factors for several variables. Subgroup analysis failed to demonstrate sufficient evidence for population differences in the relationship between PF and resilience using a random-effects model. The results of the thematic synthesis also revealed that PF has consistently been found to be related to psychological distress, resilience, and adaptation in different populations. Nevertheless, the preponderance of correlation studies, high heterogeneity, and limited number of meta-analyzed studies make it difficult to interpret any causal relationship from the results.