Psycho-physiological assessments of urban wilder nature: A systematic review and qualitative analysis with active learning screening

Background Rapid global urbanization is linked to a rising prevalence of mental health disorders. While the restorative effects of urban nature are known, there is an overlooked potential in highly natural vegetation within non-park urban green spaces, such as street verges and vacant plots. This systematic literature review aims to identify and analyze the mixed-method frameworks currently applied to empirically assess the psycho-physiological implications of highly natural urban greenery on mental wellbeing. Methods This systematic review and qualitative analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Records were retrieved from three major academic databases: Scopus, PubMed, and Web of Science, using a Boolean search string based on the Population, Intervention, Comparison, Outcome, and Study design (PICOS) criteria. Eligibility was limited to peer-reviewed empirical studies published between 2015 and 2026, written in English, Spanish, or Polish. After initial screening and removal of duplicates, an active learning-assisted screening tool, ASReview LAB was applied to efficiently screen the remaining records. The final set of 22 eligible records, which featured outdoor settings, mixed-methods, and objective psycho-physiological data, underwent a qualitative analysis. Results The qualitative synthesis included 22 primary studies. These records provide evidence of combined methodological frameworks, integrating physiological and psychological measurements, to assess the benefits of highly natural urban greenery within non-park contexts. The findings highlight the therapeutic function of green or natural infrastructure in offering non-pharmacological options for addressing health issues and emotional challenges, such as anxiety, depression, and cardiovascular issues Conclusions There is a growing trend in integrating psychological evolutionary theories and neuroscientific frameworks to understand the health-promoting benefits of exposure to urban greenery. This review synthesizes existing knowledge to inform future research avenues and evaluate current planning methodologies for cognitive restoration and mental wellbeing in non-standard urban green spaces. Systematic Review Registration PROSPERO ID: 1309399 (Under review)