New research from the University of Chicago (UChicago) that examine data from more than 400,000 people has provided new insights of the complex interaction between genetics and the environment in causing variability in common neuropsychiatric disorders. The investigators, whose findings were published in Cell Reports Medicine, are hopeful the information can be used to identify patients at risk and potentially modify their environments to protect their mental health.
“We’ve known for a long time that environmental factors have a great impact on neuropsychiatric diseases, so we wanted to look at how environmental factors interact with genetic ones,” said first author Hanxin Zhang, PhD, a research assistant at University of Chicago. “Our lab has access to the data for millions of people and their family relationships, which helps us to model shared genetic factors between family members, as well as shared environmental factors.”
The research team used health data from more than 100,000 families to create models of the genetic factors involved in some psychiatric disorders and connected it with data from the Environmental Protection Agency (EPA) based on a person’s ZIP code of where both they and their family members had lived.
Based on these models, the UChicago team determined that while genetic-environmental factors accounted for only very small variation of symptoms in people with conditions such as depression or substance abuse disorders, the variations were much greater in others including attention-deficit/hyperactivity disorder (ADHD), anxiety/phobic disorders, recurrent headaches, sleep disorders, and post-traumatic stress disorder (PTSD).
The hope is that a better understanding of the effects of environment on how certain disorders manifest will aid clinicians to help patients proactively alter their environment, if possible, to mitigate symptoms. As an example, the researchers note that if a person has a genetic variant that makes them more susceptible to migraines when exposed to a hot climate, a clinician might suggest the patient ensure their home environment is adequately air conditioned.
“Genetics is viewed by many people as something like a verdict—you can’t change it,” said Andrey Rzhetsky, PhD, senior author and a professor of Medicine and Human Genetics. “Finding these gene-environment interactions give us hope that we can find some genetic variance that interactions with the environment so that, ideally, you could change your environment and escape the disease.”
Future studies for the team include expanding the different environmental factors—beyond just the molecules in air, water, and soil—that could also affect genetic risk factors.
“In this study, we’re looking specifically at living environments and environmental exposures, but an individual’s personal experience is also a kind of exposure, especially when you are considering psychiatric diseases,” Zhang noted. “For example, understanding the interactions children have in school would be very important, but it’s very, very difficult to collect this data on a large scale.”
One potential long-term benefit of the research is to build on these data to potentially develop a lifestyle map for patients that could help tailor treatments or such methods to reduce risk of developing symptoms, Rzhetsky said.