Brain scans suggest schizophrenia is not one disease
Different abnormalities in brain anatomy match certain symptoms of schizophrenia—and not others.
Researchers say the discovery, based on MRI scans of 36 healthy people and 47 people with schizophrenia, offer more evidence that schizophrenia is a heterogeneous group of disorders rather than a single disorder.
“We just looked at the data, and these patterns began to emerge.”
“By looking at the brain’s anatomy, we’ve shown there are distinct subgroups of patients with a schizophrenia diagnosis that correlates with symptoms,” says C. Robert Cloninger, a professor of psychiatry and genetics at Washington University School of Medicine in St. Louis. “This gives us a new way of thinking about the disease.
“We know that not all patients with schizophrenia have the same issues, and this helps us understand why.”
The brain scans of people with schizophrenia showed various abnormalities in portions of the corpus callosum, a bundle of fibers that connects the left and right hemispheres of the brain and is considered critical to neural communication.
When the researchers looked at abnormalities across the corpus callosum, they found that certain characteristics revealed in the brain scans matched specific symptoms of schizophrenia.
For example, patients with specific features in one part of the corpus callosum typically displayed bizarre and disorganized behavior. In other patients, irregularities in a different part of that structure were associated with disorganized thinking and speech and symptoms such as a lack of emotion. Other brain abnormalities in the corpus callosum were associated with delusions or hallucinations.
In 2014, the same team of researchers reported evidence suggesting that schizophrenia is not a single disease but a group of eight genetically distinct disorders, each with its own set of symptoms. They found that distinct sets of genes were strongly associated with particular clinical symptoms.
The researchers believe it will be important for future studies to focus on how precise gene networks are linked to specific brain features and individual symptoms so that treatments can be tailored to patients. Currently, therapies for schizophrenia tend to be more all-encompassing, regardless of an individual patient’s symptoms.
In analyzing the clusters of genes and the brain scans, the researchers developed a complex method of analysis, similar to what companies such as Netflix use to predict movies that viewers might want to stream.
“We didn’t start with people who had certain symptoms and then look to see whether they had corresponding abnormalities in the brain,” says Igor Zwir, an instructor in psychiatry at Washington University and an associate professor at the University of Granada, Spain. “We just looked at the data, and these patterns began to emerge.
“This kind of granular information, combined with data about the genetics of schizophrenia, one day will help physicians treat the disorder in a more precise way.”
The National Institutes of Health and the Spanish Ministry of Science and Technology supported the study, which appears in the journal NeuroImage.