CAMBRIDGE, England, Nov. 17 (UPI) -- Researchers have discovered a correlation between schizophrenic hallucinations and the length of a brain fold found in the frontal lobe.
Previous studies showed that among healthy people, the length of a brain fold known as the paracingulate sulcus (PCS) corresponded with a person's ability to differentiate between real and imagined information.
The author of that study, Jon Simons, a neuroscientist at the University of Cambridge, decided to look at the same brain structure among schizophrenic patients. He found a similar pattern.
For each centimeter the a fold was shorter than the average, a patients chance of experiencing hallucinations increased by 20 percent.
"We think that the PCS is involved in brain networks that help us recognize information that has been generated ourselves," Jane Garrison, first author of the new study, said in a press release. "People with a shorter PCS seem less able to distinguish the origin of such information, and appear more likely to experience it as having been generated externally."
The study didn't link the fold with schizophrenia itself. Neurologists have shown schizophrenia to consist of a varied array of conditions linked with several different parts of the brain.
A 2014 study proved schizophrenia is actually eight disorders, not a single disease -- each with distinct genetic signatures.
But in the latest study, published this week in the journal Nature Communications, researchers found the newly discovered correlation accounted for both auditory and visual hallucinations.
"To be able to pin such a key symptom to a relatively specific part of the brain is quite unusual," Simmons told BBC News.
"Hallucinations are very complex phenomena that are a hallmark of mental illness and, in different forms, are also quite common across the general population," Garrison added. "There is likely to be more than one explanation for why they arise, but this finding seems to help explain why some people experience things that are not actually real."