The nature ”pill” for neurodiverse children and youth: a scoping review of plausible mechanisms, explanatory theories and psychosocial outcomes in ADHD and autism

Background: Recent research has demonstrated a multitude of ways in which exposure to nature enhances health and well-being. However, it is unclear whether this is true for neurodiverse children and youth, such as children on the autism spectrum and children with ADHD or Tou-rette’s syndrome.Objective: This scoping review summarizes the assumed mechanisms of change, explanatory theories, intended outcomes, and the results of studies examining the relationship between exposure to nature and psychosocial outcomes in neurodiverse children and youth.Design: We searched for peer-reviewed research reports on the relationship between exposure to nature and psychosocial outcomes in 0–18-year-old children and youth with a diagnosis of ADHD, autism or Tourette’s syndrome in six online databases with no language restrictions. The search included all years, and the final search was performed in April 2024. Animal-assisted stud-ies and studies on family outcomes were excluded. Results: This review covers 43 studies (1976–2023), primarily from North America and Europe, with 25 on ADHD and 18 on autism. Our systematic search did not identify any studies focusing on Tourette’s syndrome. The most commonly assumed causal pathways were restoring and building capacities. The most commonly mentioned theories – Attention Restoration Theory (ART) and Stress Reduction Theory (SRT) – were related to the restoring capacities pathway. Most studies adopted the medical model, viewing neurodevelopmental conditions as disorders. “Nature” was generally defined ostensively or operationally. Conclusions: Drawing on our analysis of assumed causal pathways, underlying theories, and varying definitions and conceptualizations of nature, we identify five critical research gaps to guide future studies. 1) Exploring diverse geographical and cultural contexts – more diversity is required; 2) Conceptualizing nature – what is it that provides the beneficial effects in nature? 3) A more nuanced view of pathways – it is important to align the assumed pathways with how neurodiversity is conceptualized; 4) Expanding theoretical frameworks – while most studies cit-ed ART and/or SRT, which relate to the restoring capacities pathway, explanatory theories relat-ed to the other pathways are needed; 5) Conceptualizing neurodevelopmental phenomena – there is room for building on more varied conceptualizations than the medical model, especially considering that restoring capacities and building capacities were the most commonly identi-fied pathways.