Written by Anthony Nicome, former DSIP Johns Hopkins Bloomberg School of Public Health Summer Research Intern
Litter is arguably one of the most aesthetically displeasing occurrences that plague our communities and natural environment. We find it on our sidewalks, in our storm drains, along our coastlines, beaches and remote islands, and within deep-sea vents. Walking through our country’s largest urban centers and surveying the few pieces of litter in the distance or within my immediate space, I’ve on occasion asked myself many times: how did it get there? Were these napkins strewn across the street carried by the wind after being positioned on the condiment bar at the neighborhood bodega? Or was the park bench in which a Gatorade bottle peacefully rested, adopted as a “non-traditional” trash can by its former owner? I assume that many of us have thoughts like this. For many, witnessing litter on the ground and the act of littering is upsetting. Personally, it robs me of the positive feelings that nature normally provides, and makes me wonder why individuals feel the need to use our planet as if it’s one giant trash receptacle. Research has provided the public health community a plethora of insight on the beneficial effects that nature and greened city lots have on our mental health and wellbeing. However, I’ve always wondered, what happens to an individual’s mood and overall mental health when these mentally soothing environments are impaired with litter? Does nature and/or greened lots within the built-environment provide the same positive health outcomes in a littered state as it would in a non-littered one?
Following my summer research experience at the Johns Hopkins Bloomberg School of Public Health (JHSPH), my research partner and advisor, Dr. Megan Latshaw, shared that Trash Free Maryland was interested in answering these same questions. The goal was to better understand the relationships between litter and mental health, and utilize that insight to inform an anti-litter campaign and programming. From here, I embarked on a literature review. For those not familiar with the term, a literature review is a comprehensive summary of previous research regarding a specific topic. For this review, all the articles gathered focused on the relationships between litter and mental health, and what I found was interesting!
I started the review by collecting literature from reputable scientific databases and a research journal including PubMed, Google Scholar, Web of Science, and Journal of Environmental Health. I then selected articles based on their relevancy to litter and mental health. In total, 131 peer-reviewed articles were initially generated via the use of topic-specific keywords, phrase searches, field searches, and Boolean connectors. Boolean connectors are single word phrases, “AND” (narrows a search), “OR’ (broadens a search), and “NOT” (eliminates terms from a search) which can be used to improve search results. In many of the articles, litter was found to be a sub-variable under either the “neighborhood perception” and “neighborhood disorder” variables. Because of this, the initial literature search focused on articles that included these keywords when analyzed for its relationship to mental health. Out of the hundred plus peer-reviewed articles, only eight directly analyzed the relationship between litter and health, with three published non-peer reviewed articles making it into the review. These articles were collected from academic online libraries using the same search techniques used for the collected peer-reviewed articles. Articles that analyzed litter’s relationship to physical or chronic illness were also incorporated.
To inform short and long-term strategies to address litter in communities, I had to review both the methodology and findings from the collected studies. Many of the studies used the same data collection techniques that included interviews, surveys, focus groups, and reputable statistical techniques that analyze the correlations between different variables. Depression was the most widely studied mental health disorder, while anxiety and ADHD followed. A study from Portland State University found that patients enrolled in mental health disorder treatment programs perceived litter located around their housing facility to be a factor in hindering the development of positive health outcomes associated with their current mental health recovery. Another study found that even with the introduction of new community resources, the severity of depression in littered communities remained stable or increased.2 A study analyzing marine litter used photographs to analyze the psychological impacts of visiting littered beaches.3 It was found that photographs that showed un-littered coasts tended to provide participants with a sense of happiness and less stress. In contrast, photographs exhibiting littered coasts caused participants to exhibit stress and lack of positive psychological benefits that beach destinations normally provide. Studies that used the Center for Epidemiological Depression scale and Patient Health Questionnaire to measure the correlation between litter and mental health found that patients who communicated a more negative perception of neighborhood characteristics displayed more depressive symptoms.4 Participants who communicated a more positive perception of neighborhood displayed fewer depressive symptoms.
While most of the literature that I found focused solely on the direct impacts of litter on mental health, one study revealed an indirect correlation between litter and violence. 5 Essentially, the study found litter to correlate to depression with the same incidence of depression indirectly correlating with violence.5 This finding is important because for example, if the study only focused on the direct correlation between litter and depression, crime/violence prevention professionals may have concluded violent events to be correlated to something other than litter. Because of this, eliminating violence would possibly never be completely feasible due to the stimulant (litter) not being identified. This study sheds light on the importance of understanding both indirect and direct impacts of litter on mental health; doing so allows for a more comprehensive and holistic approach in determining the relationships between mental health, litter and other environmental determinants of health.
While you may be surprised (or not), this review has developed the grounds for further research focused on exploring this environmental health issue as a community and mental health one. Although it is essential to understand the negative impacts of litter on ecosystems and various components of the natural environment, wildlife, and ourselves, little has been done to explore the direct and indirect ramifications of litter on mental health and overall quality of life. This review reveals that there is a need for more research focused on these relationships to better understand and in turn address litter not only as a threat to the physical environment, but as a threat to an individual’s mental health as well.
I hope that this review will encourage policy makers to support and pass legislation focused on reducing litter. In addition, I hope this review helps others realize that litter not only contributes to an impaired physical environment, but also impairs well-being more broadly. I believe that this research will benefit environmental non-profit organizations in providing additional reasons to sponsor campaigns that are focused on creating litter free and healthier communities. More specifically, I am encouraged that this review will drive new research initiatives aimed at understanding neighborhood-related factors in depression and other mental health disorders. Understanding these relationships will provide public health and medical practitioners further insight into treatment and prevention programs, especially for patients residing in heavily littered neighborhoods. This review begs the question, is addressing litter a way to impact mental health disorders that researchers have not fully explored?
1 Shearer, L. A. (2016) Understanding Neighborhood Satisfaction for Individuals with Psychiatric Disabilities: a Mixed Method Study. Portland State University Library.
2 Curry. (2004) Neighborhood Disorder and Depression: Multi-level Relationships at Three Levels of Aggregation. Digital Commons Network.
3 Wyles, K. J., Pahl, S., Thomas, K., & Thompson, R. C. (2016). Factors That Can Undermine the Psychological Benefits of Coastal Environments. Environment and Behavior,48(9), 1095-1126. doi:10.1177/0013916515592177
4 Perez, L. G., Arredondo, E. M., Mckenzie, T. L., Holguin, M., Elder, J. P., & Ayala, G. X. (2015). Neighborhood Social Cohesion and Depressive Symptoms among Latinos: Does Use of Community Resources for Physical Activity Matter?Journal of Physical Activity and Health,12(10), 1361-1368. doi:10.1123/jpah.2014-0261
5 Curry, A., Latkin, C., & Davey-Rothwell, M. (2008). Pathways to depression: The impact of neighborhood violent crime on inner-city residents in Baltimore, Maryland, USA.Social Science & Medicine,67(1), 23-30. doi:10.1016/j.socscimed.2008.03.007