Welcome back to the third installment of the Native Plants for Healthy People and a Healthy Planet series. Previously, we’ve discussed how incorporating native plants into our backyards and public spaces protects people from certain infectious diseases and chronic health conditions. We’ve covered biodiversity’s effects on immune system, respiratory, and cardiovascular health. This newest installment will introduce native plant biodiversity as a means of improving mental health and psychological wellbeing.
By: Helene Wierzbicki
You are likely already familiar with the benefits of nature on mental wellbeing. Countless studies have found that exposure to greenspaces and nature reduces stress and depressive symptoms. As mentioned in previous blog posts, native plant biodiversity affects long-term or chronic health in numerous ways. Exposure to natural landscapes decreases cortisol and blood pressure, improving cardiovascular health and stress management. Areas with high native plant biodiversity that mirror natural ecosystems also have positive short-term effects (up to 8 hours) on mental health (King’s College London, 2024). Multi-sensory elements of biodiverse areas–sounds, smells, and colors–have a calming effect (Myers, 2020), while regular access to natural environments decreases aggression and promotes healing (Robbins, 2020). Human interaction with different soil microbes also decreases anxiety. Specifically, the microorganism Mycobacterium vaccae has been known to increase serotonin levels and act as an anti-inflammatory agent in the brain (Marshall, 2018). As we’ve learned, increasing biodiversity of native plants improves the health of soil. By cultivating native plant landscapes, we improve their ability to positively influence our minds and bodies.
Similarly, native plants reduce depressive symptoms, such as low mood, fatigue, loss of focus, and lack of interest in activities. Depression alone accounts for a $236 billion expenditure in the United States, accounting for healthcare, work absenteeism, and self-harm fatality costs (APA, 2021). Furthermore, the loss of biodiversity can cause emotional distress in people, known as a psychoterratic response (Cianconi, 2022). In addition to their aforementioned calming effects, greenspaces allow for activities that release serotonin and endorphins, such as exercise and social interaction. One study revealed that participants who underwent a 90-minute nature walk were more likely to have decreased neural activity in areas of the brain related to negative rumination than those living in urban areas (Bratman et al. 2015). A German study indicated that people living closer to trees in urban neighborhoods were less likely to use antidepressants (Marselle, 2020). Finally, gardening boosts dopamine by triggering our innate sense of satisfaction when we find or harvest food (Francis, 2010). Spending quality time outside in native landscapes is the natural balm for urbanization.
Native plants and natural landscapes offer a reduction in psychotic symptoms as well. Psychosis is a mental disorder characterized by delusions, hallucinations, and erratic behavior or thinking patterns. The Schizophrenia and Psychosis Action Alliance estimated that schizophrenia cost the US approximately $281 billion in 2020 in healthcare and caregiving (Kadakia et al., 2022). Psychosis is caused by a combination of genetic and extrinsic factors, including environmental conditions (Ebisch, 2020). While the environment is just one of the many factors involved with the onset of a psychotic disorder, research indicates that its influence is significant. A recent Danish study indicated that children growing up in urban areas with low access to greenspace had an increased risk up to 55% of developing psychosis (Engermann et al., 2019). A similar Taiwanese study found a negative association between greenspaces and adults with schizophrenia, indicating that access to native areas may reduce the risk of developing schizophrenia (Chang et al., 2020). We can see from the research that biodiversity and access to native landscapes are an important element in mitigating some of the most intense mental health symptoms.
Folks living with severe and persistent mental illness (SPMI) are some of the most vulnerable in the community and face the most intense effects of climate change. As a psychiatric nurse, I witness and try to mitigate the worst of these outcomes. Those with SPMI are more likely to experience housing insecurity and therefore increased exposure to the elements. The likelihood of eviction or houselessness is increased in those with drug or alcohol addiction or people of color (Schutt and Goldfinger, 2009). In Oregon, few housing units come with air-conditioning units. With increasing temperatures during the summer, people living without units are at risk of overheating. Antipsychotic medication has the potential side effect of disrupting the user’s heat regulation, making them more susceptible to heat stroke (Shabir, 2021). Extreme heat events exacerbate mental health symptoms, as evidenced by higher rates of hospitalizations for psychotic or violent behavior (Rony and Alamgir, 2023). Additionally, SPMI patients often live in highly urbanized areas due to their conglomeration of social work resources (Kelly, 2022). Many research studies also conclude that people born and raised in urban areas are more likely to develop mental health disorders (Lederbogen et al., 2011). Densely urbanized areas have fewer greenspaces, so folks with SPMI do not have ready access to the psychological and physical benefits of native plants (Ebisch, 2020).
We are fortunate that so many researchers have dedicated time to establishing the connection between mental health and nature. It speaks to our common testimony that spending time in natural places–parks, gardens, backyards–benefits our bodies and minds. The evidence reveals that if we are to keep benefiting from nature, we must also act as its steward and protector. We must continue to advocate for improved access to natural landscapes and continue to restore and protect native plants for a healthy planet.
Maanch. May, 2021. https://updates.maanch.com/2021/05/covid-19-and-the-relationship-between-mental-health-and-biodiversity/
About the Series
Native Plants for Healthy People and a Healthy Planet series will explore the importance of strengthening biodiversity resilience by protecting and restoring native plants and natural landscapes. My goal in writing this blog series is to channel biodiversity through a healthcare lens and examine its relationship with human chronic, acute, and mental health. If more people understand how entwined biodiversity is with human health, perhaps policy-makers will take biodiversity resilience more seriously. Native landscapes are vital for improving health outcomes within communities. This series is made possible though the ANHE Environmental Health Nurse Fellowship Program.
The Alliance of Nurses for Healthy Environments (ANHE) is dedicated to connecting nursing and environmental health. They focus on educating nurses, advancing research, and influencing policies to promote healthier people and environments. ANHE recognizes the crucial role nurses play in addressing environmental health issues within communities and at policy levels, aiming to equip them with the necessary knowledge and leadership skills for this challenge.
About the Author
Helene Wierzbicki is a community-psychiatric nurse from Portland, OR. She works with the Washington County ACT team through the nonprofit LifeWorks NW. Helene is a fellow with the 2024 cohort of Allied Nurses for Healthy Environments (AHNE). For her AHNE project, Helene is contributing to Wild Ones through a blog series titled “Native Plants: Healthy Planet & Healthy People
References
American Psychiatry Association. (May, 2021). The Economic Cost of Depression is Increasing. Retrieved from https://www.psychiatry.org/news-room/apa-blogs/the-economic-cost-of-depression-is-increasing
Bratman, G., Hamilton, P., Hahn, K., & Gross, J. (May, 2015). Nature Experience Reduces Rumination and Subgenual Prefrontal Cortex Activation. Proceedings of the National Academy of Sciences. Retrieved from https://www.pnas.org/doi/10.1073/pnas.1510459112
Chang, H.-T., Wu, C.-D., Wang, J.-D., & Chen, P. S. (September 2020). Green Space Structures and Schizophrenia Incidence in Taiwan: Is There an Association? Research Gate. Retrieved from https://www.researchgate.net/publication/341299857_Green_space_structures_and_schizophrenia_incidence_in_Taiwan_Is_there_an_association
Cianconi, P., Hirsch, D., Chiappini, S., Martinotti, G., & Janiri, L. (2022). Climate Change, Biodiversity Loss and Mental Health: A Global Perspective. BJPsych International, 19(4), 83-86. doi:10.1192/bji.2022.20
Ebisch, S. (2020). The Self and Its Nature: A Psychopathological Perspective on the Risk-Reducing Effects of Environmental Green Space for Psychosis. Frontiers in Psychology, Vol 11. Retrieved from https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2020.531840
Engermann, K., Pederson, A., & Svenning, J. (February 2019). Residential Green Space in Childhood is Associated with Lower Risk of Psychiatric Disorders from Adolescence into Adulthood. Proceedings of the National Academy of Sciences. Retrieved from https://www.pnas.org/doi/10.1073/pnas.1807504116
Francis, R. (2010). Why Gardening Makes You Happy and Cures Depression. Djanbung Gardens, Permaculture College Australia. Retrieved from https://permaculture.com.au/why-gardening-makes-you-happy-and-cures-depression/
Kadakia, A., Catilon, M., Fan, Q., Williams, R., Marden, J., Anderson, A., Kirson, N., & Dembek, C. (October, 2022). The Economic Burden of Schizophrenia in the United States. The Journal of Clinical Psychiatry. Retrieved from https://www.psychiatrist.com/jcp/economic-burden-schizophrenia-united-states/
Kelly, B. (May, 2022). The Puzzling Link Between City Living and Schizophrenia. BBC Science Focus Magazine, Issue 298. Retrieved from https://www.sciencefocus.com/the-human-body/living-in-cities-schizophrenia
King’s College London. (April, 2024). Biodiversity is Key to Mental Health Benefits of Nature. Science Daily. Retrieved from https://www.sciencedaily.com/releases/2024/04/240416115936.htm
Marselle, M.R., Bowler, D.E., Watzema, J., et al. (2020). Urban Street Tree Biodiversity and Antidepressant Prescriptions. Sci Rep, 10, 22445. Retrieved from https://doi.org/10.1038/s41598-020-79924-5
Myers, Z. (January, 2020). Biodiversity and Our Brains: How Ecology and Mental Health Go Together in Our Cities. The Conversation. Retrieved from https://theconversation.com/biodiversity-and-our-brains-how-ecology-and-mental-health-go-together-in-our-cities-126760
Robbins, J. (January, 2020). Ecopsychology: How Immersion in Nature Benefits Your Health. Yale Environment 360, Yale School of Environment. Retrieved from https://e360.yale.edu/features/ecopsychology-how-immersion-in-nature-benefits-your-health
Rony, M.K.K., & Alamgir, H.M. (December 2023). High Temperatures on Mental Health: Recognizing the Association and the Need for Proactive Strategies-A Perspective. Health Sci Rep, 6(12):e1729. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10696165/
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Shabir, O. (July, 2021). Antipsychotics and Heat Stroke. News Medical Life Sciences. Retrieved from https://www.news-medical.net/health/Antipsychotics-and-Heat-Stroke.aspx