The risk of experiencing psychotic episodes as an adult is linked to environmental factors in childhood, in yet another example of how health is often dependent on on social circumstance.
New research from the University of Rochester Medical Center found that the more “urban” a child’s environment — meaning the more proximity to roads, pollution, houses with lead paint risk and poverty — the more likely they were to experience “psychotic-like events” within the next year.
The study describes “psychotic-like events” as delusions or subtle hallucinations. We tend to think of hallucination as a blanket term: seeing things that aren’t there, a clear sign of mental illness. But many experts say it’s more of a spectrum, and that illnesses like schizophrenia can come on slowly. Hallucinations may involve phantom sensations, for instance, or making connections that don’t exist. People might be hearing things other people don’t, or seeing shadows or flashes of light — but they may not be convinced those things are real.
People in the early stage of that kind of psychosis “lack delusional conviction,” Dr. Daniel Mathalon, an expert in the early stages of psychosis, told NPR. “They’re experiencing these things; maybe they’re suspicious. But they’re not sure.”
The kinds of delusions experienced by children in the study “can become precursors to a schizophrenia diagnosis later in life,” the researchers say.
“Past research has largely focused on the biological factors that lead to development of schizophrenia spectrum disorders,” the study’s first author Abhishek Saxena told the university’s news outlet. “But we now know that social and environmental factors can also play a large role in the risk and development of schizophrenia. And this research shows these factors impact people starting at a very young age.”
Researchers used data from the Adolescent Brain Cognitive Development Study, the largest long-term study on children’s brain development in the U.S., which included data on more than 11,000 children between the ages of nine and 11 throughout the country.
“We found that greater urbanicity was associated with greater number of [psychotic-like experiences] and associated distress measured one-year later,” the study authors wrote.
Air pollution can lead to cognitive problems
Researchers proposed a number of reasons why this might be the case. Air pollution can lead to neuroinflammation and cognitive disturbances, among other factors detrimental to brain development, which can in turn contribute to the development of psychosis. And socio-economic disadvantage (poverty, racist treatment) can “erode social cohesion,” which can lead to isolation, lack of social control, crime and paranoia. Those factors, too, can lead to psychosis in adulthood.
“These findings could have a major impact on public health initiatives to reduce the risk of psychotic-like experiences,” Saxena said.
The study suggests that potential interventions like “universal access to primary care, debt relief, or relocation to sustainable and green housing” could all help mitigate the destructive effects of poverty.
“These actions could, in theory, reduce risk for psychosis and other health conditions impacted by the social and physical environment, as well as uplift underserved populations.”