Anyone who’s grown up in the country can attest to the soothing power of nature. Clean air, greenery, peace and quiet … those are only some of the many benefits of rural living. Even suburban cul-de-sacs and man-made ponds can be places to clear one’s head and enjoy a connection to the natural world.
But a groundbreaking new study by researchers at Aarhus University in Denmark reveals that such surroundings have a far more specific effect on our mental well-being than we realize. Take schizophrenia, for instance, which often develops during adolescence and affects a person’s ability to process lucid thoughts and manage emotions. The disorder’s causes remain poorly understood, but thanks in large part to Danish national data, we now know:
People who were raised without green spaces nearby are 50 percent more likely to develop schizophrenia than those who grew up near nature.
Experts already knew the illness, which has many risk factors, tends to turn up in cities more often than in rural areas. Among the hypotheses: Schizophrenics migrate to urban areas to seek better treatment opportunities, or to disappear into the bustle of city life. But that very bustle could even be a risk factor, in addition to higher concentrations of viral illnesses. The next logical step, says study co-author Kristine Engemann Jensen of the university’s department of bioscience, was to focus on the differences between urban and rural environments. “And one of the things that’s really different is typically the amount of green space, or the type of green space, and vegetation,” she says.
The Aarhus team, which included five other researchers, used a combination of satellite imagery and data to reach their conclusion. They compared maps of Denmark depicting the distribution of green space among the population between 1985 and 2013 with statistics from the country’s national registry on people born in the same period and diagnosed with schizophrenia. Relying on a sample size of more than 940,000 — nearly a fifth of the Danish population — the researchers were able to establish that those with the least access to greenery within 200 meters of their homes were at greater risk of developing the illness.
And it’s not just a Danish matter: As the first nationwide, population-based study to demonstrate a link between green spaces and fewer cases of schizophrenia, the research may hold the key to better understanding the vexing illness more broadly. Engemann Jensen notes the same urban-rural gradient in other countries — Netherlands, Germany and Finland, for example — and in North America. “It’s probably likely we could see a similar pattern between schizophrenia and vegetation in other countries as well,” she says. But what causes the positive correlation between green spaces and the decreased risk? That, Engemann Jensen says, requires a follow-up study to build on her team’s work.
It’s probably likely we could see a similar pattern between schizophrenia and vegetation in other countries as well.
Kristine Engemann Jensen, Aarhus University
Their findings couldn’t have come soon enough. While the disorder affects only around 1 percent of the world’s population, it has proved to be both extremely disabling and difficult to understand. And while schizophrenia is treatable, limited access to quality care is also a major issue. A shocking 40 percent of schizophrenics aren’t even being treated, according to the Arlington, Virginia–based Treatment Advocacy Center, a national nonprofit dedicated to improving access to mental health care in the U.S. The World Health Organization puts that figure even higher, to more than 50 percent of the global population. Worse still, sufferers are left vulnerable to stigmatization, discrimination and other human rights violations.
Still, says Donald Goff, psychiatry professor at New York University Langone Health, the field is forging ahead with new ways to detect the illness, from genetic investigation to more refined brain imaging. The Aarhus study, he adds, could help establish a link between schizophrenia and air pollution. Either way, early identification is key. “If a person is suffering from schizophrenia, it can be disabling and stressful,” Goff says, “and the earlier they’re helped with treatment, the better.”