Researchers find a link between school-based exposure to greenness and neuronal development in children, in relation to ADHD.
A factor that has been associated with healthy development is exposure to nature. For instance, more and more research suggests that living in areas that have higher amounts of green space is associated with several health benefits. Specifically, previous studies have looked at the potential link between exposure to greenness in residential areas and ADHD symptoms and severity, but those studies have not provided consistent results.
A group of researchers from China wanted to explore this topic further and specifically focus on ‘school greenness’. They reasoned that children spend long periods of time at school and likely have more chances to use green spaces at school rather than green spaces in residential areas. In their study published in JAMA Network Open, the researchers investigated the link between greenness surrounding schools and kindergartens and ADHD symptoms in children between the ages of two and 17. Their study measured greenness surrounding schools using data they derived from satellite images.
The researchers found that there was a significant association between higher school greenness exposure and a lower likelihood of having symptoms of ADHD. When the researchers adjusted for various additional factors that could have potentially influenced the results, they found that the original association still held true. Their findings revealed that children who went to schools or kindergartens that were exposed to more greenness were less likely to have symptoms of ADHD.
The researchers noted that there is limited existing research on the effects of school-based greenness exposure on symptoms of ADHD, but there are still some studies that have looked at other measures of greenness and the effect on ADHD. Despite the findings from previous research not being identical to theirs, the researchers mentioned that the overarching trend seems to point to a positive association between higher exposure to greenness and lower levels of ADHD or symptoms of ADHD. The exact mechanism by which greenness exposure may be able to effect this change is unclear and requires further research. But the researchers proposed some possible explanations for why exposure to greenness was associated with a lower likelihood of ADHD symptoms. The researchers suggest that humans have an innate attraction to nature and as such, exposure to it could be beneficial for healthy neuronal development in children. In addition, green spaces are known to have less air pollutants and ambient noise levels, which are both factors that have been linked to problems with neurodevelopment.
Due to the possible negative outcomes associated with ADHD, the development of reliable intervention strategies has been a primary focus to help tackle the issue. The researchers note that their findings suggest that going to a school with higher levels of exposure to greenness is associated with a lower likelihood of ADHD symptoms. This has important public health implications and the findings are also relevant to healthcare authorities and policymakers.
As these findings are one of the few on school greenness exposure and ADHD symptoms, more research is required to better understand the association between the two factors. The satellite data used to measure greenness in the study provided information on the general level of greenness in the area, but it was unable to provide information on the specific nature of the greenness. This makes it difficult to understand what specific aspects of the greenness are the most closely linked to symptoms of ADHD. In addition, although the researchers did consider some external factors that could have affected the results, and adjusted for them accordingly, there were still some important factors that they were unable to account for.
Overall, the findings point to a beneficial link between exposure to school-based greenness and symptoms of ADHD but more long-term studies, as well as studies that attempt to identify the mechanism(s) by which greenness can be linked to reduction of ADHD symptoms, are required to confirm these findings and better understand the link between greenness exposure and ADHD.
Written by Haritha Thevar, BSc
Baroni, A., & Castellanos, F. (2019). Emerging Insights Into the Association Between Nature Exposure and Healthy Neuronal Development. JAMA Network Open, 2(12), e1917880. doi: 10.1001/jamanetworkopen.2019.17880
Yang, B., Zeng, X., Markevych, I., Bloom, M., Heinrich, J., & Knibbs, L. et al. (2019). Association Between Greenness Surrounding Schools and Kindergartens and Attention-Deficit/Hyperactivity Disorder in Children in China. JAMA Network Open, 2(12), e1917862. doi: 10.1001/jamanetworkopen.2019.17862
Image by F. Muhammad from Pixabay