How Early Life Experiences Shape Schizophrenia Risk

Carnegie Mellon University and University of California, San Francisco researchers found that childhood trauma, poverty, social isolation and other adverse life experiences are associated with brain changes linked to schizophrenia-spectrum disorders — findings that could help researchers identify people at risk earlier and develop interventions before severe symptoms emerge.

The idea that social determinants of health — non-medical conditions in which people are born, grow, live and work — have an out-sized role on our health is not new. In fact, some studies estimate that such conditions can account for between 30 and 55 percent of health outcomes. But how these factors impact downstream mental health conditions such as schizophrenia remains poorly understood.

“What we want to know is how these environmental factors, such as stress, trauma and poverty, get under the skin, so to speak, and affect our biology,” said Kaitlyn Dal Bon, a Ph.D. student in cognitive neuroscience in CMU’s Department of Psychology.

To better understand what is currently known about these links, Jessica Hua (right), a clinical psychologist at the San Francisco VA Health Care System and UCSF, and Dal Bon co-wrote a systematic review of 114 scientific studies that looked at early life adversity, social disconnection, racism/discrimination, poverty and food insecurity in more than 10,000 participants with schizophrenia or at risk for developing psychosis. Their findings were published today in the peer-reviewed journal JAMA Psychiatry.

Overall, the researchers found evidence that greater exposure to adverse conditions early in life is associated with differences in brain structure, brain function and neurochemistry – all of which have been previously linked to schizophrenia-spectrum disorders.

To be clear, no one factor is known to cause schizophrenia.

“One way to understand this link is to imagine that everyone has a cup, and everyone has different amounts of water in that cup, and perhaps some cups are smaller than others,” said Dal Bon. “Adding on these other factors, such as trauma or poverty, is like adding extra water to those cups. In the end, some people’s cups will overflow quicker than others.”

Importantly, the researchers said the study sheds light on how understanding social determinants of health and their associated neurobiological abnormalities could lead to improved and more targeted clinical interventions. After all, 30 percent of individuals identified as ‘clinical high-risk’ of developing schizophrenia will never convert to full psychosis and can actually remit completely.

“We know that individuals with schizophrenia are disproportionately exposed to adverse social determinants of health compared to other populations,” said Hua. “Now we need to understand how we can build resilience in these individuals, whether through focused therapy, some type of medication, family or social support, or some other kind of protective factor.”

It’s easy to misunderstand the schizophrenia spectrum as a one-way path, an end or a foregone conclusion. But research like Hua and Dal Bon’s shows that scientists are getting closer to understanding not only the factors that make a cup overflow, but those that can prevent it from getting too full in the first place.