Effectiveness of horticultural therapy in aged people with depression: A systematic review and meta-analysis.

Background: Depression, an increasing global crisis, has affected many people's daily life, especially for older adults. Horticultural therapy has been widely used in non-pharmacological treatment for patients with depression, with a body of studies demonstrating its therapeutic effects. However, a lack of systematic reviews and meta-analyses makes it difficult to get a holistic picture of this research field. Objectives: We aimed to evaluate the reliability of the previous studies and the effectiveness of horticultural therapy (including the intervention of environmental settings, activities, and duration) on older adults with depression. Methods: This systematic review was conducted under the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) guidelines. We searched relevant studies in multiple databases, and the original search was finished on 25 September 2022. We included studies using randomized controlled trials (RCTs) or quasi-experimental designs. Results: We yielded a total of 7,366 studies and finally included 13 which involved 698 aged people with depression. Results from meta-analysis indicated significant effects of horticultural therapy on reducing depressive symptoms for the older adults. Besides, we found different outcomes among various horticultural interventions (such as environmental setting, activities, and duration). Depression reduction was more effective in care-providing settings than in community settings; participatory activities were more effective in reducing depression than observational activities; intervention of 4-8 weeks might represent the optimal course of treatment compared to interventions more than 8 weeks in duration. Conclusion: We came up with a comprehensive set of recommendations based on the meta-analysis: aged people in care-providing settings with depression could get the most benefit from horticultural therapy by participating in participatory activities for 4-8 weeks. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022363134, identifier CRD42022363134.

Gut microbiota: A new target for traditional Chinese medicine in the treatment of depression.

ETHNIC PHARMACOLOGICAL RELEVANCE: The causes of depression are complex. Many factors are involved in its pathogenesis, including the individual's biological and social environment. Although numerous studies have reported that the gut microbiota plays a significant role in depression, drugs that regulate the gut microbiota to treat depression have not yet been comprehensively reviewed. At the same time, more and more attention has been paid to the characteristics of traditional Chinese medicine (TCM) in improving depression by regulating gut microbiota. In ancient times, fecal microbiota transplantation was recorded in TCM for the treatment of severe diseases. There are also records in Chinese ancient books about the use of TCM to adjust gut microbiota to treat diseases, which has opened up a unique research field in TCM. Therefore, this article focuses on the pharmacological effects, targets, and mechanisms of TCM in improving depression by mediating the influence of gut microbiota. AIM OF THIS REVIEW: To summarize the role the gut microbiota plays in depression, highlight potential regulatory targets, and elucidate the anti-depression mechanisms of TCMs through regulation of the gut microbiota. METHODS: A systematic review of 256 clinical trials and pharmaceutical studies published until June 2022 was conducted in eight electronic databases (Web of Science, PubMed, SciFinder, Research Gate, ScienceDirect, Google Scholar, Scopus, and China Knowledge Infrastructure), according to the implemented PRISMA criteria, using the search terms "traditional Chinese medicine," "depression," and "gut microbiota." RESULTS: Numerous studies reported the effects of different gut bacteria on depression and that antidepressants work through the gut microbiota. TCM preparations based on compound Chinese medicine, the Chinese Materia Medica, and major bioactive components exerted antidepressant-like effects by improving levels of neurotransmitters, short-chain fatty acids, brain-derived neurotrophic factor, kynurenine, and cytokines via regulation of the gut microbiota. CONCLUSION: This review summarized the anti-depression effects of TCM on the gut microbiota, providing evidence that TCMs are safe and effective in the treatment of depression and may provide a new therapeutic approach.