Getting outside is a good thing. You get fresh air, some sunlight and maybe even some exercise. Even just living near green space like a forest can help your overall mental health.
This proximity to green space does more than just reduce stress, however. It may also reduce the strength of risk mechanisms associated with schizophrenia, particularly during childhood.
A healthy shade of green
The causes of schizophrenia are still largely unknown to us, but ever since the 1930s, we've tracked connections between it and urban living, according to Scientific American. Urban life, with its potential for isolation and exposure to pollution, can seem to to cause enough stress that it "erodes well-being," as Diana Kwon writes for Scientific American. Urban areas can provide better access to medical care, however, pushing those who are predisposed to mental illnesses to head to the city.
A more rural environment may be the key to downplaying the effects of urban life on mental health and mitigating the known risk factors associated with schizophrenia. This is what a group of Danish researchers from Aarhus University decided to investigate.
The researchers used satellite images of green spaces in Denmark captured between 1985 and 2013. These maps were compared with data from the country's national registers for people born between 1985 and 2003 and whether or not those people developed schizophrenia.
Their results, published in the journal Schizophrenia Research in March, found that of the 943,027 people in the study, 7,509 of them were diagnosed with schizophrenia. Furthermore, those who lived in the areas with the least amount of green space faced a 1.52-fold increased risk of developing schizophrenia compared to those who lived in areas with the the most green space.
Even after factoring in urbanization, age, sex and socioeconomic status, the increase in risk held steady. Increasing exposure to green spaces helped reduce this risk, however. Green spaces were broadly defined as grassy fields, forests or even fields of corn.
"We can see that those with the least access to green spaces within 210 square meters of where they live, which is pretty close, have a higher risk of developing schizophrenia," lead author Kristine Engemann from the Department of Bioscience at Aarhus told Science Nordic.
A new understanding
As Science Nordic explained, that increase may sound like a lot, but schizophrenia affected less than 1 percent of those included in the study.
It's worth noting that the findings don't mean that just because you lack access to green spaces as a child that you will develop schizophrenia later in life. Rather, the findings point to another piece of the puzzle that is schizophrenia.
"Schizophrenia develops by a combination of many different factors, which increase the risk and ultimately lead to schizophrenia. Our surroundings are apparently one of these factors," Merete Nordentoft from the Department of Clinical Medicine at the University of Copenhagen, told Nordic Science. Nordentoft was not involved in the study.
"Smaller studies have shown that having green spaces provides stronger social cohesion and that you're more likely to get out and exercise. This can have an effect on your psychological health. So perhaps it is an indirect effect of having green spaces," she said.
As for why green spaces can reduce the risk, the Danish study didn't investigate. That will require more research.