Effectiveness of nature-based interventions in reducing agitation among older adults with dementia: a systematic review and meta-analysis

Background/Objectives: The role of environmental modifications and design in mitigating behavioural symptoms is increasingly being recognised as a way to address the psychosocial needs of individuals with dementia. This study aims to investigate various nature-based interventions for reducing agitation in people with dementia in long-term residential care environments. Methods: Database searches were conducted on MEDLINE, PsycINFO, Scopus, and Web of Science. A literature search was conducted with the following inclusion criteria: (i) peer-reviewed journal publication written in English; (ii) random controlled trials (RCTs) and quasi-experimental design with results for pre- and post-testing reported; (iii) interventions using natural elements, where the effectiveness of the reduction in agitation was measured using a validated instrument; and (iv) participants aged 65 and older with dementia residing in long-term care facilities. Results: This meta-analysis included 29 studies with 733 participants. The results showed that such interventions had a significant negative mean effect on lowering agitation in this population. Additionally, intervention settings (indoor vs. outdoor) and the presence of social interaction were significant predictors of the effect size for agitation reduction. At the same time, no significant differences in effect size were observed between the types of experiences with nature (indirect vs. direct) or the duration of the interventions. Conclusions: This study demonstrates that, when thoughtfully applied, nature-based interventions can significantly alleviate agitation in patients with dementia residing in long-term residential care facilities. This review lays the groundwork for future research aimed at developing design guidelines and planning strategies to integrate natural elements into dementia-friendly environments effectively.