The deterioration in societal mental health has occurred for decades but was accelerated by the COVID pandemic. Initially fueled by factors ranging from a rapidly urbanizing landscape to inaccessibility of quality mental health resources and awareness, over 19% of adults experienced mental illness in 2019 (The State of Mental Health in America), suggesting that this crisis is widespread. Research conducted by Mental Health America showed that “Suicidal ideation continues to increase among adults in the U.S. 4.58% of adults report having serious thoughts of suicide, an increase of 664,000 people from last year’s dataset.” (The State of Mental Health in America). Poor mental wellness is now the second most common type of disability in America, as reported by the Social Security Administration (Annual Statistical Report on the Social Security Disability Insurance Program, 2020). As such, practical solutions for this crisis are urgently needed.
While several complex solutions have been proposed, one of the simplest remedies may be encouraging people to spend more time outside, amongst greenery (green foliage or plants). This seemingly mild home remedy, often prescribed by loved ones, has shown promise in clinical research as a means of helping to control the onset of mental illness while also alleviating some of the early symptoms. A 2019 study in Denmark found that greater access to greenery in childhood significantly reduced the risk of psychiatric disorders later in life (Engemann et al., 2019). In this study, involving 943,027 Danish residents, the researchers used satellite images of participants’ childhood homes to determine the amount of yearly green space each participant received while growing up. This data was then compared to their medical records later in life to assess the mental health outcomes of the residents over time. After controlling for several factors, including urbanization, parental wealth, family history, parental age, and other municipal socioeconomic factors, the researchers found that living with lower levels of green space was associated with a 15-55% greater risk of developing mental health disorders later in life. Risks were lowered as the amount of green space experienced in childhood increased. Hence, early exposure to greenery may be an effective preventative measure against mental health challenges (Engemann et al., 2019).
However, foliage may be effective not only when it is experienced in childhood but also in adulthood. A 2014 study found that greater exposure to green spaces was correlated with better mental and physical health across several demographics (Dzhambov et al., 2021). In this study, the researchers assessed the mental health status of 8,793 adult Catalan (European) participants using standardized questionnaires and compared that data with satellite images of their homes to find connections between mental health and the amount of green space exposure. After analyzing their findings, the researchers found that having green spaces within 300 meters of residential areas was consistently correlated with lower likelihoods of poor health across many of the measures of health tested (even after controlling for socioeconomic differences). Furthermore, their analysis also revealed that even when residents did not have access to vast green spaces such as parks and fields, greenery such as trees and plants was also an effective restoration and stress reduction method. Thus, surrounding greenery could be an effective method for staving off chronic mental illness even when large areas of greenery are unavailable (Triguero-Mas et al., 2015).
While going outdoors is vital in experiencing the benefits of green spaces, research also suggests that indoor greenery, such as houseplants, could also have beneficial effects. One study analyzed this effect by measuring how greenery experience correlated with the mental health of homebound students during the COVID-19 quarantine. This study involved 323 students from two Bulgarian universities who were asked to fill out an online survey about their present mental status and proximity to greenery. The researchers then used standardized point scales to process the information, revealing that having access to indoor and outdoor greenery was strongly correlated with lower depression/anxiety levels and thus lowered the rates of clinical depression and anxiety rates during the study period. Secondly, the research also suggested that while less potent than the combined effect of both indoor and outdoor greenery, experiencing greenery only indoors, via an average of 10 houseplants, was also associated with significantly lower levels of depression/anxiety. The researchers concluded that while experiencing green spaces indoors and outdoors was necessary for the best benefits, indoor greenery alone could also effectively control mental illness if access to more open spaces is not possible (Dzhambov et al., 2021).
The studies presented here are a few of several that provide evidence to strongly suggest the use of green spaces is beneficial for mental wellness. While the mental health crisis is a complex societal struggle, something as small as taking a daily walk in the park or incorporating a few plants into workspaces could be an effective tool against this challenge. Hence, while seeming simple initially, trees and plants may be our strongest allies in this fight for better mental wellness.
Key Takeaways:
More access to greenery when young is associated with better mental wellness in adults
Having green spaces within 300 meters of residential areas was consistently correlated with higher chances of good health
Having access to both indoor and outdoor greenery was strongly correlated with lower depression and anxiety levels
Indoor greenery (an average of 10 houseplants) alone may also effectively control mental illness if access to more open spaces is not possible
Written by Tanishq Vaidya and edited by Aldrin V. Gomes, PhD
References
Annual Statistical Report on the Social Security Disability Insurance Program, 2020. Retrieved April 8, 2022.
Dzhambov, A. M., Lercher, P., Browning, M. H. E. M., Stoyanov, D., Petrova, N., Novakov, S., & Dimitrova, D. D. (2021). Does greenery experienced indoors and outdoors provide an escape and support mental health during the COVID-19 quarantine?Environmental Research, 196, 110420.
Engemann, K., Pedersen, C. B., Arge, L., Tsirogiannis, C., Mortensen, P. B., & Svenning, J. C. (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 of the United States of America, 116(11), 5188–5193.
The State of Mental Health in America, Mental Health America. Retrieved February 7, 2022.
Triguero-Mas, M., Dadvand, P., Cirach, M., Martínez, D., Medina, A., Mompart, A., Basagaña, X., Gražulevičiene, R., & Nieuwenhuijsen, M. J. (2015). Natural outdoor environments and mental and physical health: Relationships and mechanisms. Environment International, 77, 35–41.