In February, a study was published in the Journal of Psychiatric Research investigating the links between exposure to pollution and difficulties with mental health. The study was a systematic review—that is, a meta-examination of a wide range of existing research on the topic—and was co-led by Dr Kristin Hadfield of the Trinity Centre for Global Health.
The study found that exposure to air and water pollution “was associated with elevated symptoms of depression, generalised anxiety, psychosis, and/or disruptive, impulse control and conduct disorder”, and that lead and solvent exposure was also linked to “neuro-developmental impairments”. Trinity News spoke to Dr Hadfield about what motivated her research, and what she thought the implications and policy outcomes from the study could be.
What inspired you to complete the study?
We were inspired to begin this study because we thought there might be a connection between the following two things: First, a large proportion of people have mental health difficulties, and most of these begin in early adolescence. Second, many people are exposed to high levels of pollution in their day-to-day lives.
We know that pollution causes a wide range of physical health problems. There has also been a lot of research on how families, peers, and schools influence young people’s mental health, but limited research on the broader environmental factors. We wanted to bring these two factors together to try to understand how pollution impacts mental health in teenagers.
Are climate issues something you have always been interested in?
My interest in climate issues has grown as I have personally seen the impacts of climate change and pollution exposure. It’s very sobering reading the Intergovernmental Panel on Climate Change reports. I do my best in my own life to limit my environmental impact and also advocate for change in Trinity and in Dublin.
That said, this research comes from a place of trying to understand how to prevent the development of mental health difficulties in young people or how to treat difficulties when they arise. My research broadly focuses on how best to promote positive mental health and reduce psychopathology among children and adolescents, and one potentially important but very understudied influence is the environment.
What was it like working on a study with multiple researchers from several universities?
Because I do global health research, much of my work is with large groups of scientists across different universities and in different countries. I think it’s critical when you have a very complex issue that you bring in different perspectives so that you can study it in a more rigorous way. This project included psychologists, biologists, geneticists, and public health researchers from five different countries (Ireland, South Africa, Brazil, the UK, and Argentina). Given that a vast majority of the world’s children and adolescents are living in low- and middle-income countries, and that people in lower income countries are more likely to be exposed to dangerous levels of pollution, it was also very helpful to have the perspectives of colleagues in South Africa, Brazil, and Argentina in this review.
Prof Linda Theron and I co-led the study. She is a world renowned expert in youth resilience based at the University of Pretoria in South Africa. She is also involved in a few other projects looking at climate and environmental impacts on teenagers.
What results struck you most from this study?
I was surprised by a few things. First, that there has been a lack of research attention on how pollution impacts teenagers’ mental health. Our systematic review found evidence for pollution impacts, but there were many fewer studies than I expected, and the studies were not as high-quality as the types of studies examining pollution exposure and physical health. If governments are concerned about the mental health of young people, it is important to know what leads mental health problems to develop. Pollution is a potential risk factor for mental health difficulties but we know very little about which pollutants, what mental health problems, what the pathways of impact are, etc, because there just hasn’t been the research. I was really surprised by this.
Second, the evidence that we do have suggests that when teenagers are exposed to pollution—particularly air and water pollution—they have more depressive symptoms, anxiety symptoms, conduct problems, and more issues with psychosis.
Third, almost no studies have investigated what could support the mental health resilience of adolescents when they are exposed to pollution. Young people will be exposed to pollution and so it was surprising to see that very few people have studied how to prevent this pollution exposure from having negative impacts on their mental health.
Finally, I was really shocked that there have been no studies on how noise pollution impacts teenagers’ mental health. I believe that noise pollution may be very negative for people’s mental health, but we actually don’t have any research on this at all, anywhere in the world.
What impact do you hope your study will have on those reading it?
I hope that people will begin to consider that pollution exposure is not just a risk to physical health and to our broader environment, but may also be leading to mental health problems.
What steps do you think need to be taken in light of the results? For example, what can Trinity specifically do?
I think Trinity could do a few things. To protect the air quality that students and staff are exposed to, all non-disabled parking could be removed from campus. Further, Trinity could lobby Dublin City Council for better public transit, cycling, and pedestrian facilities between and to the Trinity campuses. Finally, Trinity could monitor the air, water, noise, and land pollution that students and staff on campus are exposed to; monitoring is an important first step to understanding what changes—if any—need to be made.
Outside of Trinity, it would be great if funding bodies would put resources into investigating how pollution exposure impacts child and adolescent mental health. Because we know so little, it’s difficult to know what interventions might be most helpful.
What do you think students can do to alleviate climate issues, if at all?
While many of the critical changes need to come from government regulations, infrastructure changes, and from businesses, there are some things that we can all do to reduce how much pollution we produce and our climate impacts. We can reduce our meat intake, drink less or no dairy, not use a car to travel except where absolutely necessary, etc. It’s also important to get active with the local and national governments and to tell policymakers what types of changes you want to see.
How can students look after their mental health in light of the results?
The results of the review unfortunately don’t provide much guidance on how to look after your mental health, but aside from pollution exposure, the following can be useful in promoting good mental health: keeping active, keeping in close contact with supportive family and friends, sleeping on a regular schedule, using the coping strategies that work for you, paying attention to the positive things that happen to you each day, and asking for help when you need it.